 |
Wiki
PHYSICAL ACTIVITY HELPS ATTAIN THE GOOD LIFE
"Lack of activity destroys the good condition of every human being, while movement and methodical physical exercise save it and preserve it." ~Plato
Physical Activity is the expenditure of energy beyond resting level through muscle activation, which can arise in any situation, including occupational and domestic tasks.
Physical Exercise is a form of Physical Activity. It involves a repetitive, structured, leisure-time pursuit with the goal of maintaining physical fitness, function or health.
(Salmon 2001; Dishman et al, 2006; Casperson et al 1985).
Is there a single answer to increasing happiness, boosting brain power, enhancing physical attraction and self-acceptance, and improving overall wellbeing and leading a good life? You would expect this to be a complex answer, but evidence suggests that simple physical activity may do all of this. While certain areas in Positive Psychology have been too easily dismissed, the theory that physical activity can somehow improve and maintain mental well-being has been investigated again and again, and the evidence appears to support the suggestion that physical activity does in fact help attain the good life.
Contents
4 Historical and Cultural Connections 6 Mechanisms for Positive Change 6.2 Indirect effects of exercise |
Key Paper
- Hamer, M., Stamatakis, E. and Steptoe, A., (2008). Dose Response Relationship between Physical Activity and Mental Health: The Scottish Survey. British Journal of Sports Medicine
Summary of the theory
The case for physical activity as an aid to mental wellbeing has gathered firm support worldwide in recent years. According to Fox (1999), there are four different aspects involved in the direct contribution to solving mental health problems through physical activity. These include the treatment of mental illness and disorders; the prevention of mental illness and disorders; the improvement of mental and physical well-being of those with mental illness; and the improvement of mental well-being of the general population. Many highly regarded clinical and practical applications have been deduced from this theory and the Government has given its full support to implementations aiming to increase the mental and physical health of the British population through the medium of physical activity.
The Scottish Executive believes so strongly in this theory that in 2003 they employed the ‘Lets make Scotland More Active’ strategy along with thePhysical Activity and Health Alliance. The aim of this programme is to improve mental and physical health of 50% of adults and 80% of children through physical activity by 2022.
This theory continues to achieve results and gain support and can definitely be considered influential in the realm of Positive Psychology.
Recommended References
Journals
- Mental Health and Physical Activity - Available via Science Direct.
A recently developed journal (live as of 2008) focussing soley on the publication of high quality research which aims to shed light on the association between physical activity and positive mental health. This journal provides a great introduction to this topic with many relevant and recent experimental investigations enabling a critical evaluation of the area. Available through
Research Articles
- Whitelaw, S., Swift, J., Goodwin, A., and Clark, D. (2008) Physical Activity and Mental Health: the role of physical activity in promoting mental wellbeing and preventing mental health problems. An Evidence Briefing. NHS Health Scotland
This paper examines fully the effect of physical activity on mental well-being as well as other aspects of the brain and body. It was written by researchers from the University of Glasgow and is highly relevant to this area of investigation.
- Van Praag (2009). Exercise and the brain – Something to chew on. Trends in Neurosciences. Volume 32, Issue 5, May 2009, Pages 283-290:
An interesting current article that looks at the effects of exercise on brain health. This article also discusses that fact that the effects of exercise can be enhanced by a healthy diet through an equal discussion of exercise and diet (However, don’t let this joint topic put you off reading this article, because the info on exercise alone is clear and concise and we also highlighted the fact that exercise and diet may be more closely related than you think). The part of this article that focuses on exercise starts by highlighting that exercise not only mitigates various diseases, but actually has benefits on the brain. It gives a background summary of the studies that have been carried out in relation to the brain and cognition in both humans and animals and then goes onto discuss the biochemical mechanisms that mediate the effects of exercise on the brain. It is also a good starter point for more current citations related to exercise and its apparent positive effects on the brain.
- Church, T.S and Blair, S.N., (2009) When will we treat physical activity as a legitimate medical therapy even though it does not come in a pill? British Journal of Sports Medicine , 43: 80-81
A very recent article briefly discussing the benefits of physical activity to both general health and as a treatment of various ailments and illnesses. Short but very interesting; it questions the current evidence in this area and asks for further investigation into how we can achieve the best results using this free resource so widely available to us.
Historical and Cultural Connections
History of Exercise
The claim that exercise improves health and well-being has a long history. Exercise consciously implemented as a means of improving health can be traced back to as early as 2500 BC in China (Lyons et al, 1978). The ancient Greeks were also prominent in promoting physical well-being through exercise and fitness; in particular the philosopher Plato is well remembered for ‘Mens Sana in Corpore Sano’ which defines the Greek ideal of physical and mental health (Macauley, 1994). Greek youth were strongly encouraged to undertake physical exercise as a fundamental part of education programmes, and this was also understood to have a much larger standing in the area of health in that exercise was seen to be beneficial to treating disease and disability (Macauley, 1994). The importance of exercise to the Greeks became even more evident with the development of athletics festivals, namely those held in Olympia which has to this day been maintained and practiced in the form of what we know as the Olympics.
Furthermore, the physician Claudius Galen, born around 131 AD, promoted exercise for the health of the body and intellect (Macauley, 1994) and according to Green (1951) Galen attributed his own physical and mental health to regular exercise. He quotes “the habit of the mind is impaired by faulty customs in food, drink and exercise…and these constitute the beginnings of severe diseases.”
Although the benefits of exercise may have been identified many years ago and in particular the long-term physical benefits of exercising have long been established, the actual study of the psychological benefits of exercise is a relatively new area of research which is becoming increasingly under the spotlight in the area of positive psychology (Scully et al., 1998). The scientific investigation of the relation between exercise and cognition began in the 1930’s and examinations began in the 1970’s into the relationship between physical conditioning and reaction times which tended to show positive correlations (Hillman et al., 2008). Newer research has been conducted into understanding the brain mechanisms which lie behind the effect exercise has on cognition.
Early Investigations
According to Simons et al. (1985), early studies which have focused on physical exercise as a means of increasing positivity, and in particular in reducing depressive symptoms, have been limited in their usefulness in terms of design issues and conceptual problems.
In most of the early studies in this field, nonexperimental designs were employed which failed to control for certain variables which could produce effects which could be misinterpreted as evidence for or against exercise effects. They say that the most prominent of these design faults lie in the large differences between subjects tested and non-random treatment assignment.
Simons and others (1985) also note that in the early debate of whether exercise has any psychological benefit in the treatment of depression, conceptual errors were often made which casts doubt on the findings. These include confusion among what they constitute as subjects, treatments and outcomes. They state that many of the early journals they reviewed do not make the important distinction between subjects with depressed mood and those who have actually been diagnosed with a depressive disorder, and similarly use subjects that have other disorders besides depression which are perhaps more serious. The use of exercise as a treatment for depressive episodes cannot be taken as a treatment with a single dimension, rather it can vary in terms of intensity, frequency and duration. Recent studies account for this fact however research prior to 1985 and perhaps later failed to conceptualise exercise treatments in these specific terms. Furthermore exercise treatment studies carried out prior to the review provided by Simons do not consider the outcomes as having different levels or the distinct factors which exist in outcomes. These studies have tended to focus solely on the amount of change expected from a patient treated in a particular way and have ignored many important factors including safety and acceptability of the treatment.
Similarly, a far more recent review by Backhouse and others (2007) has outlined flaws in pre-1990’s studies, mainly the fact that they focused on the effects of exercise on the individual both before the exercise and at a range of time points after the exercise, but never during the exercise period. They attribute this to the initial assumption that any changes which arise before and after engaging in exercise will be linear, however the authors mention more recent work which has shown that both moderate-intensity and high-intensity exercise can actually cause a decrease in positive feelings during the exercise session and an almost immediate rise in these feelings after the exercise session has stopped. Therefore it seems sensible to account for the changes which may arise during exercise.
Unusual Claims
A massive amount of research supports the idea that physical activity aids mental health. This ranges from positive self-concept, more self-esteem and more positive "moods" to higher levels of alertness and mental ability, including the ability to learn.
Unlike other areas in positive psychology, there appears to be firm evidence behind many of these theories; and it is universally acknowledged that physical activity does have a positive effect on the mental state.
At a glance, many of the claims made regarding this area seem extreme to say the least. It is difficult to imagine that physical activity could so heavily influence aspects of a person’s wellbeing. However, many of these theories are supported by accurately collected evidence.
Physical Activity can Heal the Mind
The idea that physical activity can improve intelligence seems like a strange concept. While this seems like an impossible scenario, Castelli et al. (2007) concluded that physical fitness is in fact associated with an improved academic preformance in primary school children. Radak et al (2001) also lent weight to this argument with the suggestion that regular exercise can improve cognitive function.
In a study of 600 students in Taiwan, Li et al (2009) reported that participation in physical activity can increase emotional health. This led them to conclude that it can also be attributed to an improvement in emotional intelligence.
Physical activity is claimed to significantly improve symptoms of depression. While medications are often used to control this illness, Blumenthal et al. (1999) studied 156 sufferers of major depressive disoder. Some patients received only a drugs treatment, some used exercise and medication together; and some only used exercise as a treatment. Results determined that all three groups improved significantly to the same extent. This implies that exercise can be used as effectively as medication when treating depression.
Physical Activity can Heal the Body
Claims made by The Natural Resources Canada include the suggestions that physical activity can reduce the risk of developing colon cancer; of dying prematurely and of developing diabetes. While a number of studies acknowledge physical activity as an influencing factor in determining how long and healthy a life will be (Ferrucci et al. 1999), it is difficult to find conclusive evidence that it alone can increase your life expectancy. It tends to be examined as part of an all-round healthy lifestyle (i.e: not smoking, eating well etc.) and therefore may not be a significant factor on its own.
Exercise has been investigated both as an aspect of the colon cancer recovery process (Courneya et al. 2003) and as a preventative measure. Samad et al. (2005) concluded that a strong body of evidence supports the idea that physical activity can reduce the risk of colon cancer development in both males and females; while it poses no defense against the development of rectal cancer. Their study was global and so also negates cross cultural differences.
There appears to be a large body of evidence supporting claims regarding diabetes risk. A review paper spanning over 300,000 participants concluded that moderate intensity activity such as brisk walking can significantly reduce the risk of developing type 2 diabetes. The paper included studies involving males and females and found the effect to remain constant across the sexes.
The menopause can be a stressful and very uncomfortable experience for many middle-aged women. Physical activity has recently been examined as a potential method of reducing the negative impact this period can have on women. While limited, the initial research supports this idea; concluding that physical activity can have long-term benefits for menopausal females. Elavsky (2009) reported that physical activity carried out by females going through the menopause was associated with higher levels of self-worth .
Physical Activity can make us more Attractive
Professional Dating Coach Jessica Claire claims that exercise can make a person more attractive; and that men should take up a physical activity in order to attract women. While this is a fairly far-fetched notion in itself, Fox (1999)concluded that physical activity can improve self-perceptions and possibly global self-esteem. A boost in self-confidence can positively affect how others perceive us (Ellis, 1992) and therefore could result in others being more attracted to us.
While some of these claims have received more support than others, it is clear that physical activity does in fact have a positive effect on many aspects of both the mental and physical state. As a result of the vast amount of research carried out in this field, it is difficult to find claims regarding the benefits of physical activity which are not backed by at least an element of validated evidence. One point worth noting however, is that limitations such as the methodology used and whether physical activity is always a determining factor in studies should always be taken into account before accepting such claims.
Mechanisms for Positive Change
Scully and colleagues (1998) pointed out that the primary mechanisms underlying the relationship between exercise and psychological wellbeing were not very well understood and that the majority of the literature was descriptive. Meaning that the relationship between exercise and wellbeing was described, but researchers had shied away from exploring the possible explanations for the interaction.
However, a decade later, Whitelaw et al (2008) outlined six possible explanations for the nature of the association between exercise and mental health and there is now much more focus on exploring these areas. These six areas included ‘biochemic al & physiological; Improvements in fitness and weight loss; Mastery of a new task; Distraction from stress in our lives; social interaction and sense of belonging; and, social and cultural value. The following section will give a taster of some of these areas.
Its important to look at the evidence.. In recent years many schools in the USA have actually stopped the compulsory PE requirements in an attempt to increase students academic performance in standardised testing. This may be an example of action being taken for an apparent good cause that can actually create harm as no actual evidence exists to back this idea up.
Exercise and the brain ![]()
Physical Activity benefits Cognition... The neural correlates of mathmatics and reading comprehension have been identified as activiating a similar network to the area realted to fitness, so this would would be a first hint that increased physical activity might actually create benefits in school performance. As in most fields, there are some studies that suggest that there is no relation between physical activity and academic performance, however the method used by one such study relied on the self-reported perception that the teacher had of their students physical activity, which is a questionable measure. Also, the majority of other studies in the area indicate that there is a positive relationship. The general idea is that exercise in childhood might increase the resilience of the brain in later life as well as making a functional difference in the present.
Neurogenesis in the brain: Could physical activity actually help us grow new neurons?... A large amount of research in animal studies (the methods used on animals would be clearly unethical in humans) has indicated that proliferation (growth or production of cells) or cell survival has increased in the dentate gyrus of the hippocampus due to exercise treatment. (For example, Eadie et al, 2005). A brain-derived neurotrophic factor (BDNF) is a molecule involved in neurogenesis, neuroprotection, and learning and memory operations and this is reported to increase with exercise, but even more so when combined with Estrogen. This relation between exercise and estrogen could explain Colcombe et als (2003) meta-analysis results. Colcombe revealed that exercise interventions with a higher ratio of females compared to males showed greater enhancing effects of exercise on cognition than those with a greater male ratio to females.
More on BDNF and Catecholamines as mediators by which physical exercise improves learning... Winter and colleagues (2007) looked at whether exercise had an immediate effect on cognition and revealed that intense running had a positive effect on vocabulary learning. Their study found that higher levels of BDNF was related to success of learning in the short-term and that dopamine and epinephrine levels were also related to increased (intermediate and longterm) retention of novel vocabulary. There are many studies in this area that show that exercise releases positive mood inducing chemicals like seretonin and dopamine. A related example of exercise creating a chemical change is the Runners High (a self-reported euphoric, calm, clear state after long aerobic exercise). The mechanisms of this state are widely debated, initially the answer put forward was endorphins, but doubt has been cast on this theory. Then it was suggested that seretonin and dopamine may play a part and now the most recent evidence suggests that it is related to a chemical called phenylethylamine (also found in Chocolate) - for more info see Runner's high links in reference section.
Why Physical activity might make our minds sharper and quicker... Reseach has indicated that in all age ranges (children through to older adults) physical activity is related to faster processing and quicker directing of attention. One brain mechanism for this that has been revealed is the larger amplitude and shorter latencies of P3 component in the brain (For more info see the studies cited in Hillman et al, 2008). Hillman and collegues (2003) showed that reaction time was improved by cardiovascular exercise and pointed towards the neuroelectric processes (P3 amplitude) as an explanation. They also highlighted that a more sophisticated understanding of the relationship (and mechanisms) between exercise and mental health is needed in order to use exercise as a potential tool for improving and protecting mental health.
Self Concept and social interaction as a mediator:
Exercise has been shown, in line with most peoples intuitions, to have a positive effect on our attitude about our body. (especially found in older women). One study showed that an Aerobic Dance Exercise intervention increased satisfaction with body image which in turn increased self-esteem of middle aged women. This was able to contribute to an overall improvement of the quality of the lives of the women. (Tihanyi Hős, 2005).
Physical Exercise as a 'gateway' to positive changes
There is suggestion that participating in physical exercise leads indirectly to the adoption of other behaviour patterns. This is hypothesised to occur quite naturally, without directed effort on the part of the agent. If this is the case, it may be that a proportion of the beneficial effects of exercise are the result of beneficial new habits which evolve of their own accord.
Nutrition
Tucker and Reicks ran a study in 2002 to explore this concept in relation to exercise and food intake (Tucker and Reicks, 2002). Subjects answered on a questionnaire of how much exercise they undertook and this rating was compared against another questionnaire detailing their eating habits. It was found that subjects in an advanced stage of an exercise program were more likely to eat more healthy food items more often. Additionally, subjects in a later stage of an exercise program were more likely to report being in a later stage of positive behaviour change for fruit and dairy product consumption.
However, a recent paper by Dutton et al conflicts with these findings (2008). In this study, exercise was not found to be predictive of fruit and vegetable intake and was related to increased fat intake. In evaluating these claims by Dutton et al, it is important to note two things:
i) Participants in the study were already consuming five portions of fruit and vegetables per day. This being the case, what improvement could realistically have been expected?
ii) Calorie intake was not measured. It may be that the increased fat intake of participants undertaking exercise was indicative of increased eating in general - which would be expected – rather than negative food type decisions.
Despite these doubts, the positive effect of good nutrition on mental well-being is well known (Malt et al., 2008). Exercise and nutrition may be related but it is not clear cut in the literature. Perhaps physical exercise may indirectly increase the likelihood of better nutritional choices, thus amplifying its own positive effects.
Smoking
Evidence which suggests that exercise also modulates smoking behaviour is accumulating (Taylor et al., 2006).
A recent research project by Janse Van Rensburg et al sheds some interesting light on why this may be (Janse Van Rensburg et al, 2009). Participants were invited into the lab for a session of exercise followed by an MRI scan. In addition to finding that a brief exercise session decreased cigarette cravings up to fifteen hours later, the scan component showed that the pattern of brain activation differed between the exercise and control groups.
In both the exercise and control groups, participants were shown smoking related images while undergoing an MRI scan. In the non-exercise group, the scan revealed activation in the precentral gyrus, parahippocampal gyrus and caudate nucleus structures, all thought to be involved in reward processing. In the exercise group there was a substantial reduction in activation at these sites and an increased reaction instead in areas of the frontal lobe associated with higher cognitive functioning. Janse Van Rensburg et al's findings suggest therefore that exercise exerts tangible effects on the brain, making the individual less inclined to smoke.
However a behavioural study by Everson et al (2006) that looks at whether Exercise reduces the desire to smoke in a younger population actually shows that, unlike the research involving adult populations, short bouts of exercise does not reduce the desire to smoke or withdrawal symptoms among abstaining adolescents. In fact the Psychological distress scores were actually higher for those in the exercise group. It may be that the processes underlying the effect of exercise in adolescents is different from older adults, but further research is needed to investigate this.
Alcohol Intake
In 2004 Ussher et al. found that 10 minutes of moderately intense cycling significantly reduced alcohol urges for their participants during the activity period (Ussher et al., 2004). Although these findings point to a welcome indirect effect of exercise, support for a 'gateway' hypothesis linking exercise and alcohol consumption, is initially limited. It is interesting but not quite useful on its own to know that exercise limits alcohol cravings while exercising. However this is a definite a starting point for further thought.
In 1986, Murphy and colleagues examined the effect of an aerobic exercise program on a heavy drinking cohort of university students (1986). They found that participants on the exercise program significantly cut down their drinking compared to the control group. Importantly, this study was not an explicit attempt to curb participants' alcohol intake: The dependent measure of alcohol consumption was disguised by many behavioural variables unrelated to drinking such as mood, sleep and eating habits which were included as distractors. These results therefore lend weight to the suggestion that exercise can exert positive influence on other behaviours with or without one's own directed effort.
Sleep
Physical activity can have far reaching effects on wellbeing and health. One area of research that has been shown to be particularly important to our wellbeing, our health and our cognitive function, especially memory, is sleep (Walker, 2008). There is also evidence that physical activity improves sleep quality (see Review by Driver and Taylor, 2000 for a discussion of this), which would suggest that some of the positive effects we see in everyday life and longer time framed studies is due to an indirect link through the mechanism of a good nights sleep.
Summary
Overall this is just a taste of some of the mediators and mechanisms that current research has pointed to, but it shows that there is strong evidence to suggest that physical exercise really does have the ability to effect us in more ways than we know. Studying mechanisms is important as it can lead to a better understanding of the process and it could also help focus the creation of positive interventions, which particularly support these mechanisms.
Clinical Applications
Current situation within the UK Health Services
Physical activity is not a new application within UK health services. However, only recently has it been thought of as an empirically effective concept taking priority over, or equality with existing physical and psychological therapies in terms of tackling mental illness.
A recent publication from the Joint Health Surveys Unit (2003) states that at least six out of ten males and seven out of ten females are not physically active enough to reap the benefits of good health. According to the Department of Health (2004), at least 30 minutes of moderate activity is recommended five times a week for the healthy population, with most effective activities being walking, jogging, cycling, swimming and dancing. They also make a clear link between physical inactivity and ill health – both psychological and physical. So what is being done within the current UK health service to improve physical activity within a clinical population?
Current NICE guidelines (‘Four commonly used methods to increase physical activity: brief interventions in primary care, exercise referral schemes, pedometers and community-based exercise programmes for walking and cycling’, 2006) suggest possible methods of achieving this, including brief interventions in primary care (offering opportunistic advice and encouragement), exercise referral schemes targeting high risk groups, and the use of pedometers and walking and cycling schemes, suggested by the Public Health Interventions Advisory Committee (PHIAC). NICE guidelines (‘Treating Depression in adults with a long-term physical health problem’, 2009) also advise regular exercise for those diagnosed with mild to moderate depression.
In terms of the recommended intensity and duration of physical activity for the mentally ill, evidence is strongest for activity lasting between 20 and 60 minutes (Department of Health, 2004) moderate in intensity. It is argued that exercise must not be too strenuous or demanding on individuals for numerous reasons; it may enhance levels of stress rather than reduce them (National Institute of Health, 1996), and patients will be more likely to continue an exercise regime if it is not too physically demanding of them (Thirlaway & Benton, 1992). As for type of exercise applied, there are no set guidelines within the NHS to advise carers of what to specifically recommend to patients. However, D’Silva (2002) found that activities such as martial arts are effective for treating depression, weights and running for self-confidence issues, boxing and tennis for anger, and non-competitive sports such as yoga and swimming for treating existential angst.
There is currently a community gym project in Barrow-in-Furness that specifically applies exercise as a therapeutic intervention for mental illness (Callaghan, 2004). They consider the individual needs in providing motivation and support for patients suffering from mood disorders to psychosis. However, there is limited empirical evidence to support the effectiveness of this programme and it is unknown whether or not patients undergoing an exercise programme at this community gym were on psychological or pharmacological therapies alongside their physical therapies.
Empirical Evidence to Support Clinical Applications
On what empirical basis are these physical activity programmes or applications being applied to a clinical population? Lee and Skerrett (2001) found that adults up to the age of 80 who are physically active have a 20%-30% reduced risk of a premature death, whilst the Department of Health (2004) reported that it reduces the risk of developing a major chronic disease such as coronary heart disease, stroke, diabetes and cancer – by half. Multiple studies have also found evidence for an inactive lifestyle of between 8 and 30 years is positively associated with clinical depression (Cammacho et al, 1991; Farmer et al, 1988; Paffenberger et al, 1994). Simiarly, studies have found that physical activity regimes reduce the risk of developing a mental illness; whereby it stands as an effective treatment for mild, moderate and even severe clinical depression (Craft & Landers, 1998; Lawlor & Hopker, 2001; Mutrie, 2000). Furthermore, it has been shown to be as effective as both psychotherapy (Lawlor & Hopker, 2001; Mutrie, 2000) and anti-depressants after a 16 week study (Blumenthal et al, 1999) and a 6 month study (Babyak et al, 2000).
Students are advised to refer to Callaghan (2004) and Fox (1999) for extensive reviews on the effectiveness of exercise as an intervention for mental health disorders.
Several suggestions have been made in an attempt to comprehend why physical exercise has been shown to benefit mental illness. The Department of Health (2004) puts forth 3 categorical explanations; being biochemical mechanisms (an increase in circulatory plasma and serotonin), physiological mechanisms (an increase in core temperature and cerebral blood flow and reduction in muscular tension and neurotransmitter efficiency), and psychosocial mechanisms (an increase in physical and mental competence and confidence). It could be further argued in terms of psychological benefits that the change in daily routine, opportunity for socialisation, positive body perception and a sense of mastery could also be factors for helping improve psychological function.
However, it is important when reviewing studies investigating the effectiveness of physical activity to be aware of the role of physical fitness. In other words, is it the increase in fitness that helps target depression, or is it simply the physical activity itself that helps it. This is brought to mind with respect to North et al (1990), who found that exercise had a better effect on those patients who were the unhealthiest at the start of the experiment. Therefore, only those who had increased their physical fitness and had experienced the greatest physical changes to their body had the most benefits from their exercise programmes. It would therefore be wise to determine the effects of physical activity over a long-term period as opposed to a short period.
To conclude, most studies do find an effect for physical activity in reducing mental illness, however one paper in particular (Geddes et al, 2003) maintains from experimental evidence that exercise has only limited effectiveness for treating depression. Babyak et al (2000) found that exercise had similar effects on MDD than anti-depressants. However when combined, there was no advantage. This is a fairly surprising find; it is generally thought that two effective interventions combined would produce a positive effect. Perhaps patients both undertaking an exercise regime and a course of anti-depressants feel that the effects of the drugs will take care of their illness and therefore don’t gain the psychological motivation and hope that the physical activity would normally promote.
Is Exercise an effective intervention for various other mental health disorders and physical illness?
So does physical activity interventions help only specific clinical populations? We have seen so far that it can be effective in helping mood disorders such as depression, but what about anxiety disorders, personality disorders and even physical disease?
Again, the Department of Health (2004) provides evidence that physical exercise can help prevent and/or manage diseases such as coronary heart disease, stroke, diabetes and cancer, with most effective activities being walking, jogging, cycling, swimming and dancing. Competitive sports are only effective if subjects are already used to them in some form of routine.
O’Connor et al (2000) have also found physical activity to be beneficial in treating Generalised Anxiety Disorder, phobias, panic attacks and general stress, whereas Faulkner & Biddle (1999) provided evidence to suggest it affects psychological well-being in schizophrenia. A similar study by Faulkner & Sparks (1999) has shown that exercise reduces auditory hallucinations, raises self-esteem and aids sleep in a schizophrenic population.
Students are advised to refer to the Unusual Claims section of this wiki for more information regarding exercise as an intervention for physical disease.
Practical Applications: Physical Activity can be fun too!
For testing the effects of exercise we focus on activities that we can control for other potential causes, However when it comes to interventions for health it is more important to find ones that have positive results. One problem with exercise mentioned was the paradox, that although it is good for you and makes you feel better, people rarely enjoy the process or thought of doing the exercise itself. This is not the case for all physical activity - and Dance is a prime example of this. When people dance they often forget that they are exercising because they are caught up in other things like music, concentrating and having fun. Time passes and they find they have been active for an hour or more.
Dance has been shown to have positive effects on psychological wellbeing and fitness level in general. Using Dance as an intervention has recently attracted a lot of attention and support. Due to the nature of Dance, it may be that various positive Psychology factors are coming into play. For example, the meditative quality of dance; the ability to express emotions through dance (which is what a form of psychotherapy called dance therapy makes use of); and, the social character of dancing with others. One large report published by Lablan in 2007 (Quin et al, 2007) assesses the effects of a 10-week creative dance programme on school children and shows that creative dance benefits the physiological and psychological health of young people. In regards to the psychological wellbeing of children, results found positive adaptations, although not statistically significant, in all areas assessed (self-esteem, intrinsic motivation and attitude towards dance).
Relaxing, non-competative sports such as yoga and pilates have also been known to promote wellbeing and a sense of calm whilst being fun and enjoyable. Do sports such as these also help mental illness?
A recent paper by Javnbakht et al (2009) found that participation in a 2 month yoga class can significantly reduce anxiety but NOT depression in women, and supports the idea that yoga can be used as either a complementary or alternative therapy for anxiety disorders. However, an extensive systematic review by Kirkwood et al (2005) found that there is not enough evidence to suggest that yoga is effective in treating anxiety disorders but found promising results for treating obsessive compulsive disorder.
Exercise Enjoyment and Catering Exercise to your tastes
Other research has suggested that different ways of exercising can produce varying positive emotions. Plante et al (2006) carried out a study where participants either went on a brisk walk around a university campus, were given a virtual reality headset and watched the same walk through this headset whilst not exercising or thirdly, watched this presentation but whilst on a treadmill. From this it was found that the outside walk gave the most energizing effect but indoors on the treadmill was most relaxing. This suggests that it is important to look at surrounding mood when exercising. If the person wants to use exercise to relax, then an inside environment may be better suited but if they want to feel revitalized then outside will be more beneficial.
Another study by Plante et al (2007) investigated whether positive benefits of exercise were increased when women exercised with a friend. They found that for the exercise to have a relaxing effect, they were better carrying out the exercise on their own. Again, this suggests that is important to adapt the environment to the type of positive gain you wish to receive from exercising.
Gaps and Criticisms with the Research
The stumbling block
The problem is, if exercise is good for us why don’t we want to exercise?! A study in 1992 found that 70% of men and 80% of women did not do the recommended level of exercise (Allied Dunbar National Fitness Survey, 1992) and since then we have probably got lazier! If, as many different fields such as social psychology and neuroscience have shown, we tend to do things that make us feel better and avoid things that don’t how does exercise fit into this? A lot of previous research has ignored this clear contradiction.
This debate is covered very well in Backhouse et al. (2007).
Main points from article
-sometimes negative feelings during exercise are discounted by researchers as they are seen to be replaced by the positive feeling at the end.
-not enough studies monitor mood right through the exercise- they just measure mood at the start and end so cannot assume there is a linear relationship throughout. The mood change during exercise may well hold the key to why people do not continue exercising.
-negative consequences are not expected so appropriate measures which might pick them up are not used. This may mean the research misses their presence.
-It cannot be assumed that everyone has the same response to exercise. Some people may report a decrease in mood whilst in others it increases, which would not be shown in a group average.
The effect of exercise in a wider population
Non-clinical studies have suggested more mixed results in terms of whether physical exercise improves mood. Two separate studies found that the participants in their study who were not anxious or depressed to start with did not show mood enhancement following exercise (Dishman 1986, Frazier and Nagy 1989). In Hassmén et al (2000) well-being was looked at through there being a lack of negative affect. The researchers also looked at how much the person felt that they were personally in control of their health and their life, their perceived fitness and sociability.
Those who exercised more reported lower scores on negative affect and higher on positive affect.
This seems to suggest that exercise helps prevent depressive symptons in the normal population. Those who exercised regularly also appeared to take more responsibility for the state of their own health, this perhaps explains partly why they exercise more. However, the most interesting finding is that it seems that moderate exercise is the most beneficial for wellbeing. Those who exercised to a vigorous extent on a daily basis were more depressed than those who only exercised moderately. It was the moderate exercisers (those who exercised two or three times a week and those who exercised once) who showed the lowest depression scores.
This suggests that a balance needs to be gained between exercising more for your wellbeing and not overdoing it!
Methodological Issues
1.Appropriate Control Groups
One of the problems pointed out by Yeung (1996) in the methodology of these studies is with studies such as West (cited in Penedo and Dahn, 2005) where participants were put in yoga, dance class or a lecture. Yeung suggests this is not a good control condition, as some people may request and prefer to be in the lecture condition. This would mean personality may become a confounding variable. It is also not a true control as the lecture may adversely or positively affect the participant’s mood state, depending on how interesting the lecturer is! Also there is debate still about whether both aerobic and non-aerobic exercises, such as yoga, have a beneficial effect as an antidepressant (argued from both sides in Scully et al, 1998). It may be the case that the yoga class had different positive benefits from the dance class, as the dance class may have given a sense of energy whilst the yoga class may appeal more to those who want to use physical exercise to relax.
2.Correlational Evidence
There is also much correlation evidence cited to support the beneficial effect of exercise. This includes evidence presented in Penedo and Dahn (2005) which suggests that depression rates are lower among physically active people and sports players. Or that in a large sample of adolescents, those who participated in physical activity outside school had less depressive symptoms over a two year period. Here the problem is that it cannot be distinguished whether this lower prevalence of depressive symptoms is due to their physical activity or whether it is due to their more active personality. Again, this is the case with Hassmen et al’s (2000) study which although great for surveying a larger sample of 3403, has the problem of being correlational.
A study by McAuley? et al (2005) used a control group and an active condition group that were both made up of older people who were not exercising. Those in the group taking part in more exercise and receiving more social support through the exercise programme had increased levels of wellbeing at the end of the study, when compared to the other group who did a stretching control. This was found after 1 month of increased exercise which suggests that if this was continued it would have significant positive effects. This study is helpful because both the control and the active group were not people who exercised much before, therefore any positive effects found are much more likely to be caused by the increased exercise.
3. When should mood be measured?
It would also be of benefit to have more studies that measure how people feel at different points in the exercise cycle- to find out if it is just at the end that people feel the positive effects of exercise or whether it is something that builds during the exercise. Backhouse et al (2007) carried out a study to try and counter the lack of research into this area. They found from this that participants showed a mixture of emotions through the course of exercise from energy to exhaustion, tension to calmness. This suggests that there is a more detailed picture of what effect of mood exercise actually has that is still to be fully investigated.
4. The need for larger samples of the non-clinical population
The main problem with much of the research is that they focus on clinical populations. Some studies that have looked at the wider population have found that physical activity is beneficial to health, but not when it becomes extreme exercise. Yeung (1996) reports several studies (Douchamps-Riboux et al 1989 and Berger and Owen, 1992) where the competitive or highly demanding nature of exercise resulted in the person’s mood being worse following exercise. Rejeski (cited in Scully et al, 1998) found that there was a ceiling effect with exercise. This research suggested that low to moderate exercise was best to enhance mood and psychological function but if this got too demanding, it would do less psychological good. This finding was reinforced by Zervas et al (1993) who found that people who were able to exercise at their own level made the greatest mood improvement, suggesting that it is important to begin at a level the person is capable of. This links to the topic of Flow- the idea of matching a person’s abilities to the challenge presented. This makes sense as an overweight person isn’t going to enjoy high intensity exercise so much when they are more physically uncomfortable than a fit person through increased perspiration (Backhouse et al, 2007).
References
General (and other)
Scully, D., Kremer, J., Meade, M. M., Graham, R., and Dudgeon, K. (1998). Physical exercise and psychological well being: A critical review. Br J. Sports Med. 32: 111–120
Penedo, F., and J.R. Dahn, (2005) Exercise and well-being: a review of mental and physical health benefits associated with physical activity, Curr Opin Psychiatry 18, pp. 189–193.
Hassmen, Koivula & Uutela (2000). Physical Exercise and psychological Well-Being: A Population study in Finland , Preventive Medicine, 30(1), 17-25.
Giacobbi, P.R., Tuccitto, D.E. and Frye, N. (2006) Exercise, affect, and university students’ appraisals of academic events prior to the final examination period. Psychology of Sport and exercise. 8, 2, pp.261-274 - (This article is 'appropriately' focused on what Physical exercise has to offer as a coping response to demanding academic situations; specifically, how exercise effects the emotions of University students approaching their exam period. Suggests that increased exercise might provide an emotional respite from stressful circumstances during the highly demanding academic period just before the exams. On the other hand, it was also suggested that exercise may actually increase the severity of negative affect when events are seen as highly threatening.)
History
Backhouse S.H., Ekkekakis P., Biddle S.J.H., Foskett A., Williams C. (2007). Exercise Makes People Feel Better But People Are Inactive: Paradox or Artifact? Journal of Sport and Exercise Psychology, 29: 498-517
Hillman, C.H., Erickson, K.I. and Kramer, A.F. (2008) Be smart, exercise your heart: exercise effects on brain and cognition, Nature Reviews Neuroscience 9 , 58-65 (Worth reading -This article examines the positive effects of aerobic physical activity on cognition and brain function, at the molecular, cellular, systems and behavioural levels.)
MacAuley? ? D. (1994). A history of physical activity, health and medicine. Journal of the Royal Society of Medicine, 87: 32-35
Scully, D., Kremer, J., Meade, M. M., Graham, R., and Dudgeon, K. (1998). Physical exercise and psychological well being: A critical review. Br J. Sports Med. 32: 111–120
Simons A.D., McGowan?? C.R., Epstein L.H., Kupfer D.J. (1985). Exercise as a Treatment for Depression: An Update. Clinical Psychology Review, 5: 553-586
Mechanisms
Tihanyi Hős, A (2005) The effect of Guided Systematic Aerobic Dance Programme on the self-esteem of Adults. Kinesiology 37, 2:141-150
Sibley, B.A. and Etnier, J.L. (2003) The relationship between physical activity and cognition in children: a meta-analysis, Pediatric Exercise Science. 15, pp. 243–256
Hillman, C.H., Pointfex, M.B., Raine, L.B., Castelli, D.M., Hall, A.A., and Kramer, D.F. (2009) THE EFFECT OF ACUTE TREADMILL WALKING ON COGNITIVE CONTROL AND ACADEMIC ACHIEVEMENT IN PREADOLESCENT CHILDREN. Neuroscience 159 Pp.1044–1054.(This data suggest that single bouts of exercise affect specific underlying processe - like P3 amplitude- that support cognitive health and may be necessary for effective functioning across the lifespan.)
Hillman, C.H., Erickson, K.I. and Kramer, A.F. (2008) Be smart, exercise your heart: exercise effects on brain and cognition, Nature Reviews Neuroscience 9 , 58-65 (Worth reading -This article examines the positive effects of aerobic physical activity on cognition and brain function, at the molecular, cellular, systems and behavioural levels.)
Hillman, C. Snook, E. and Gerome, G. (2003), Acute cardiovascular exercise and executive control function, International Journal of Psychophysiology 48, 307–314
Eadie, B. D., Redilla, V. A. & Christie, B. R. (2005). Voluntary exercise alters the cytoarchitecture of the adult dentate gyrus by increasing cellular proliferation, dendritic complexity, and spine density . J. Compar. Neurol. 486 , 39–47
Winter, B. Breitenstein, C. Mooren, F.C., Voelker, K. Fobker, M. Lechtermann, A. Krueger, K. Fromme, A. Korsukewitz, C. Floel, A. Knecht, S. (2007) High impact running improves learning, Neurobiology of Learning and Memory 87, 597–609
Boecker, H.,Sprenger, T., Spilker , M.E. , Henriksen, G., Koppenhoefer, M., Wagner, K.J., Valet, M., Berthele, A. and Tolle, T.R. (2008) The Runner's High: Opioidergic Mechanisms In the Human Brain. Life Sciences and Medicine, Cerebral Cortex. 18, 11, pp252-2513.
Runner's High website links: http://en.wikipedia.org/wiki/Endorphin#Runner.27s_high or http://serendip.brynmawr.edu/biology/b103/f02/web1/sfrayne.html#6 Both websites give an insight into the fact that the mechanisms and reasons for the runners hgh are still under a large amount of debate.
Walker , M.P., (2008) Cognitive consequences of sleep and sleep loss. Sleep Medicine 9 Suppl. 1S29–S34
Kramer, A. F., Erickson, K.I (2007) Capitalizing on cortical plasticity: influence of physical activity on cognition and brain function. Trends in Cognitive Sciences, Vol 11, Issue 8, pp 342-348. - (A discussion of 6 directions for future research in considering the cognitive and neural effects of exercise. Including consideration of the fact that exercise effects are not independent of other factors, like estrogen, diet and social engagement)
Lindwall, M. and Lindgren, E. (2005). The effects of a 6-month exercise intervention programme on physical self-perceptions and social physique anxiety in non-physically active adolescent Swedish girls Psychology of Sport and Exercise, 643–658 (Includes discssion of direction of effects possible mechanims, limitations of the study and practical applications linked to xercise and modern diseases.)Everson, E.S., Daley, A.J. Ussher, M. (2006) Does exercise have an acute effect on desire to smoke, mood and withdrawal symptoms in abstaining adolescent smokers? Addictive Behaviors 31, 1547–1558
Clinical Applications
Babyak M, Blumenthal JA, Herman S, Khatri P, Doraiswamy M, Moore K, et al. (2000). Exercise treatment for major depression: Maintenance of therapeutic benefit at 10 months. Psychosomatic Medicine, 62: 633-638.
Blumenthal JA, Babyak MA, Moore KA, Craighead E, Herman S, Khatri P, et al.(1999).Effects of exercise training on older patients with major depression. Archives of Internal Medicine,159: 2349-2356.
Callaghan, P. (2004). Exercise: a neglected intervention in mental health care? Journal of Psychiatric and Mental Health Nursing, 11, 476-483.
Camacho TC, Roberts RE, Lazarus NB, Kaplan GA, Cohen RD. (1991). Physical activity and depression: Evidence from the Alameda County Study. American Journal of Epidemiology, 134: 220-231.
Craft LL, Landers DM.(1998) The effect of exercise on clinical depression and depression resulting from mental illness: A meta-analysis. Journal of Sport and Exercise Psychology, 20: 339-357.
D’Silva, B. (2002). This sporting life. The Observer Magazine, 29th September, 77-78.
Department of Health (2004). At Least Five A Week: evidence on the impact of physical activity and its relationship to health. A report from the Chief Medical Officer. London : Department of Health.
Farmer M, Locke B, Moscicki E, Dannenberg A, Larson D, Radloff L. (1988). Physical activity and depressive symptoms: The NHANES 1 epidemiological follow-up study. American Journal of Epidemiology, 128: 1340-1351.
Faulkner G, & Biddle S. (1999). Exercise as an adjunct treatment for schizophrenia: A review of the literature. Journal of Mental Health, 8:441-457.
Faulkner, G. & Sparkes, A. (1999). Exercise as therapy for schizophrenia: an ethnographic study. Journal of Sport and Exercise Psychology, 21, 52-69.
Joint Health Surveys Unit. (2003). Health Survey for England 2003. London : The Stationery Office.
Lawlor DA, Hopker SW. (2001).The effectiveness of exercise as an intervention in the management of depression: systematic review and metaregression analysis of randomised controlled trials. British Medical Journal, 322: 1-8.
Lee, I.M., & Skerrett, P.J. (2001). Physical activity and all-cause mortality: what is the dose response relation? Medicine and Science in Sports and Exercise, 33, S459-S471.
Mutrie N.(2000). The relationship between physical activity and clinically defined depression. In: Biddle SJH, Fox KR, Boutcher SH, editors. Physical activity and psychological wellbeing. London : Routledge, 46-62.
National Institutes of Health (1996). NIH Consensus Development Panel on Physical Activity and Cardiovascular Health: Physical activity and cardiovascular health. JAMA 276: 241–246.
NICE (2006) Four Commonly used methods to increase the physical activity: brief interventions in primary care, exercise referral schemes, pedometers and community-based exercise programmes for walking and cycling. London ; National Institute for Clinical Excellence.
North, T.C., McCullagh??, P. & Tran, Z.V. (1990). Effects of exercise on depression. In: Exercise and Sport Sciences Reviews (eds Pandolf, K.P. & Holloszy, J.O.), pp. 379-415. Williams & Wilkins, Baltimore.
O’Connor PJ, Raglin JS, Martinsen EW. (2000) Physical activity, anxiety and anxiety disorders. International Journal of Sport Psychology, 31: 136-155.
Paffenbarger RS, Lee I-M, Leung R. (1994). Physical activity and personal characteristics associated with depression and suicide in American college men. Acta Psychiatrica Scandinavica, 89: S16-S22.
Thirlaway, K. & Benton, D. (1992). Participation in physical activity and cardiovascular fitness have different effects on mental health and mood. Journal of Psychosomatic Research, 36(7), 657-665.
Practical Applications
Javnbakht, M., Hejazi Kenari, R. & Ghasemi, M. (2009). Effects of yoga on depression and anxiety of women. Complementary Therapies in Clinical Practice, 5, 102-104.
Kirkwood, G., Rampes, H., Tuffrey, V., Richardson, J., Pilkington, K. (2005). Yoga for anxiety: a systematic review of the research evidence. British Journal of Sports Medicine, 39, 884-891.
Dance UK Report: New report proves creative dance benefits the health of young people. (Online Link to Briefing, Research Report and Evaluation report.)
Dutton, G., Napolitano, M., Whiteley, J., Bess, M. (2008) Is physical activity a gateway behavior for diet? Findings from a physical activity trial. Preventive Medicine 46 (2008) 216–221
Quin, E. Redding, E., and Fraser, L. (2007). The effects of an eight-week creative dance programme on the physiological and psychological status of 11-14 year old adolescents: An experimental study. Dance Science Research report. Lablan.
Hassmén, P., Koivula, N., Uutela, A., (2000) Physical exercise and psychological well-being: A population study in Finland, Preventive Medicine, 30, 17-25, 2000
Malt, E. A., Malt, U. F., Muller, H., and Pederson, J. I. (2008) Nutrition, diet and mood. Journal of Affective Disorders 107 (2008) S21–S52
Murphy, T. J., Pagano R., and Alan Marlatt, G. (1986) LIFESTYLE MODIFICATION WITH HEAVY ALCOHOL DRINKERS: EFFECTS OF AEROBIC EXERCISE AND MEDITATION . Addictive Behaviors, Vol 11 pp. 175-186, 1986
Plante, T.G., Gores, C., Brecht, C., Carrow, J., Imbs, A., and Willemsen, E., (2007) Does Exercise Environment Enhance the Psychological Benefits of Exercise for Women? International Journal of Stress Management, 14, 1, 88–98
Plante, T.G., Cage, C., Clements, S., and Stover, A., (2006) Psychological Benefits of Exercise Paired With Virtual Reality: Outdoor Exercise Energizes Whereas Indoor Virtual Exercise Relaxes, International Journal of Stress Management, Vol. 13, No. 1, 108–117
Janse Van Rensburg, K., Taylor, A., Hodgson, T., Benattayallah, A. (2009) Acute exercise modulates cigarette cravings and brain activation in response to smoking-related images: an fMRI study. Psychopharmacology (2009) 203:589–598 DOI 10.1007/s00213-008-1405-3Taylor, A., Ussher M., and Faullkner G. (2006) The acute effects of exercise on cigarette cravings,withdrawal symptoms, affect and smoking behaviour: a systematic review. Addiction, 102, 534–543
Tucker, M., Reicks, M. (2002) Exercise as a Gateway Behavior for Healthful Eating among Older Adults: An Exploratory Study. J Nutr Educ Behav. 2002;S14-S19
Ussher, M., Sampuran, A., Doshi, R., West, R., and Drummond C. (2004) Acute effect of a brief bout of exercise on alcohol urges. Addiction, 99, 1542–1547
Gaps in Research and Criticisms
Backhouse S.H., Ekkekakis P., Biddle S.J.H., Foskett A., Williams C. (2007). Exercise Makes People Feel Better But People Are Inactive: Paradox or Artifact? Journal of Sport and Exercise Psychology, 29: 498-517
MacAuley? ? D. (1994). A history of physical activity, health and medicine. Journal of the Royal Society of Medicine, 87: 32-35
Yeung, R.R., (1996) The Acute Effects Of Exercise On Mood State , Journal of Psychosomatic Research, 40, 2, 123-141
Zervas, Y., Ekkekakis, P., Emmanuel, C., Psychoudaki, M., Kakkos, V., (1993) The acute effects of increasing levels of aerobic exercise intensity on mood states. In S. Serpa, J. Alves, V. Ferreira, A. Paulo-Brito (eds), Proceedings of the 8th World Congress of Sport Psychology Lisbon, Portugal.
Dishman R.(1986) Mental health, In: Seefeldt V, ed. Physical activity and well-being. Reston, VA: AAPHERD, 303–41
Frazier SE, Nagy S. (1989) Mood state changes of women as a function of regular aerobic exercise, Perceptual Motor Skills, 68 :283–7.
Unusual Claims
Blumenthal, J.A, Babyak, M.A., Moore, K.A., Craighead, W.E., Herman, S. and Khatri, P., (1999) Effects of exercise training on older adults with major depression, Archives of Internal Medicine, 159: 2349-2356Castelli DM, Hillman CH, Buck SM, Erwin HE. (2007) Physical fitness and academic achievement in third- and fifth-grade students. Journal of Sport and Exercise Psychology; 29: 239–252. (Physical activity was found to be associated with total academic achievement, mathematics achievement and reading achievement, which suggests that aspects of physical fitness may be globally related to academic performance in preadolescents)
Courneya, K.S., Freidenreich, C.M., Quinney, H.A., Fields, A.L.A., Jones, L.W. and Fairey, A.S. (2003) A randomised trial of exercise and quality of life in colorectal cancer survivors, European Journal of Cancer Care, 12: 347-357
Ellis, B.J in Barkow, J.H, Cosmides, L. and Tooby, J. (1992) The Adapted Mind: Evolutionary Psychology and the Generation of Culture, Oxford University Press, New York
Ferrucci, L., Izmirlian, G., Leveille, S., Phillips, C.L., Corti, M., Brock, D.B. and Guralnik, J.M., (1999) Smoking, Physical Activity and Active Life Expectancy, American Journal of Epidemiology 149: 7: 645-653
Fox, K.R. (1999). The influence of Physical activity on mental well-being. Public Health Nutrition: 2(3a), 411-418
Li, G.S., Lu, F.J.H., Wang, A.H., (2009) Exploring the relationships of physical activity, emotional intelligence and health in Taiwan students. Journal of Exercise Science and Fitness, 7 (1) 55-63
McAuley? ? , E., Elavsky, S., Jerome, G.J., Konopack, J.F., and Marquez, D.X., (2005) Physical Activity-Related Well-Being in Older Adults:Social Cognitive Influences, Psychology and Aging, 20 (2), 295–302
Radak, Z., Kaneko, T., Tahara, S.,Nakamoto, H., Pucsok, J., Sasvari, M., Nyakas, C. and Goto, S., (2001) Regular exercise improves cognitive function and decreases oxidative damage in rat brain, Neurochemistry International, 38 (1) 17-23
Samad, A.K.A., Taylor, R.S., Marshall, T. and Chapman, M.A.S., (2005) A meta-analysis of the association of physical activity with reduced risk of colorectal cancer, Colorectal Disease, 7:3: 204-213
Steriani, E., (2009) Physical Activity, Menopause and Quality of Life: the role of affect and self-worth across time. Menopause 16:2: 265-271
Moodle Docs for this page