The case for exercise and health has primarily been made on its impact on diseases such coronary heart disease, obesity and diabetes. However, there is a very high cost attributed to mental disorders and illness and in the last 15 years there has been increasing research into the role of exercise a) in the treatment of mental health, and b) in improving mental well-being in the general population. There are now several hundred studies and over 30 narrative or meta-analytic reviews of research in this ?eld. These have summarized the potential for exercise as a therapy for clinical or subclinical depression or anxiety, and the use of physical activity as a means of upgrading life quality through enhanced self-esteem, improved mood states, reduced state and trait anxiety, resilience to stress, or improved sleep.
The purpose of this paper is to a) provide an updated view of this literature within the context of public health promotion and b) investigate evidence for physical activity and dietary interactions affecting mental well-being. The case for exercise and physical health is now widely accepted by medical authorities across the world. Sedentary living doubles the risk of morbidity and mortality from coronary heart disease and stroke which is comparable with the risk associated with hypertension and hyperlipidemia and not far behind that of smoking. In addition, low activity levels are thought to be a major cause of obesity and a contributor to the rising incidence of diabetes and some cancers. The incidence of inactivity is also high in many developed countries where technology is slowly removing exercise from lifestyles and is estimated at around 40% of the middle aged and elderly in the UK. The public health burden of inactivity is therefore problematic and expensive and activity promotion could provide a cost-effective strategy for improvement. While physical activity can indirectly improve subjective well-being and life quality by keeping disease and premature death at bay, there has recently been an increasing interest in its direct role in the prevention and treatment of mental health problems. Mental illness and disorders are widespread and possibly on the increase.
The first publication in a scientific journal of exercise as treatment for clinical depression was published over a century ago. Franz & Hamilton reported favorable outcomes following exercise in emotional, cognitive and bodily symptoms in two severely depressed patients. Later randomized controlled studies have confirmed this observation and demonstrated that exercise is associated with an antidepressant effect.
How does exercise help depression and anxiety? Regular exercise may help ease depression and anxiety by releasing feel-good endorphins, natural cannabis-like brain chemicals (endogenous cannabinoids) and other natural brain chemicals that can enhance your sense of well-being. Taking your mind off worries so you can get away from the cycle of negative thoughts that feed depression and anxiety. Regular exercise has many psychological and emotional benefits, too. It can help you Gain confidence. Meeting exercise goals or challenges, even small ones, can boost your self-confidence. Getting in shape can also make you feel better about your appearance. Exercise and physical activity may give you the chance to meet or socialize with others. Just exchanging a friendly smile or greeting as you walk around your neighborhood can help your mood.
Doing something positive to manage depression or anxiety is a healthy coping strategy. Trying to feel better by drinking alcohol, dwelling on how you feel, or hoping depression or anxiety will go away on its own can lead to worsening symptoms. The first randomized controlled study comparing exercise with other forms of treatment was published by Greist and colleagues in 1979. They compared aerobic exercise with time-limited and time-unlimited psychotherapy, finding exercise to be equal to time limited and better than time-unlimited therapy. In a second study, they compared exercise with group psychotherapy and meditation, finding no significant differences among the conditions at the end of the treatment period.
At 1-year follow-up, the exercisers had kept their gains in both studies. Later investigators have compared exercise with cognitive therapy and general counselling, finding no significant differences between them. In recent years, several publications have reported positive effects of physical activity on mood.
However, the validity of their conclusions has been limited by methodological problems. Principally, reports do not describe the type, intensity, or frequency of exercise programs used as therapeutic intervention; therefore, the results are difficult to reproduce. Several studies have described an improvement in mood of healthy persons after participation in a physical activity program.
However, care needs to be taken when applying these findings to patients with affective disorders. A general problem of reports on the effects of exercise on depression is the lack of information about the psychiatric diagnosis of participants according to standard references—for example, the Diagnostic and Statistical Manual of the American Society of Psychiatry (DSM IV). Furthermore, most reports provide inadequate information about the characteristics of the sample. For example, two studies enrolled university students with elevated scores on depression scales such as the Beck Depression Inventory; however, participants were not defined as being clinically depressed. In some studies, exercise programs were started or carried out at the same time as pharmacological treatment or psychotherapy. Thus, the relative effects of the two interventions on the observed outcomes cannot be differentiated. Finally, the high percentage of drop outs in most studies renders interpretation of their results difficult. Despite these problems, most of the evidence indicates positive effects of physical activity on mood.
Two meta-analyses suggest that exercise may be as effective as psychotherapy and more effective than other behavioral interventions for treating depression. A few studies have used true experimental designs to evaluate the effects of exercise on mood. In the first one, 43 female students with elevated scores in the Beck Depression Inventory were randomly assigned to one of three groups (endurance training, relaxation training, or no treatment). After 10 weeks, depression scores improved significantly in the endurance training group but were unchanged in the relaxation and control groups. In a recent study, resistance training over 10 weeks was more effective than a placebo activity to reduce depression scores in elderly people. Finally, in a further study, 40 clinically depressed women carried out one of two exercise programs (running or weight lifting), or were included in a waiting group without training. After eight weeks, depression scores were significantly lower in both intervention groups than in the controls. Blumenthal and colleagues have performed two well designed randomized controlled trials.
In the first study, supervised group exercise three times a week was compared with antidepressant medication and the combination of the two in the treatment of major depression. Those who received antidepressants improved faster, but at 12 weeks, all groups were improved and there were no significant differences among them. Ten months after the exercisers had kept their gains to a larger extent.
In the second study, antidepressant medication was compared with placebo, supervised group-based exercise and individual home-based exercise, both three times a week. After 4 months, 42% achieved remission, and patents receiving active treatments tended to have higher remission rates. There were no significant differences between the two forms of exercise and antidepressant medication. A large proportion of patients who receive antidepressant medication do not respond adequately. Mather and colleagues studied patients with clinical depression who had not responded to antidepressant medication in adequate doses. These were randomly assigned to exercise and health education classes, and exercise was significantly more effective. Trivedi and colleagues also found exercise to be useful in the management of non-responders to medication.
A fundamental issue concerns the minimal effective dosage of exercise needed to improve depression. Dunn and colleagues studied the dose response relation of exercise and reduction in depressive symptoms in patients with major depression who exercised individually. They found that those who exercised, according to the public health recommendations, three to five times a week with a weekly energy expenditure of 17.5 kcal/kg/ week, had significantly larger reductions in depression, compared with those who exercised with low intensity and a weekly energy expenditure of 7 kcal/kg/week. The association between exercise and anxiety has received comparatively less attention, and the majority of studies have examined the transient psychological outcomes of single exercise sessions. The general finding is that state anxiety is significantly reduced following bouts of exercise, both for subjects with normal or elevated levels of anxiety.
These reductions are statistically significant within 5 – 15 min after the cessation of exercise and remain decreased for the following 2 – 4 hours, before gradually returning to pre-exercise levels. In contrast, the influence of long-term exercise programs on trait anxiety is less consistent. Leading to the possibility that you can become tolerant of exercise and possibly reduce its effects on your anxiety reduction. The majority of people know that exercise is beneficial, but this knowledge does not guarantee starting or sticking with an exercise program. A consistently beneficial method for improving exercise compliance has yet to be identified, and researchers continue to examine the motivation to exercise.
Prochaska & DiClemente state that motivation is not a stable phenomenon, but a process that evolves through several discrete stages. Their research indicates that to be effective, any behavioral intervention intended to improve exercise compliance must be tailored to the motivational stage of the individual, a technique called treatment matching. Because many persons with depression or anxiety are inactive and low in fitness, they probably are not ready to change, but rather ambivalent to making changes in lifestyle. With treatment matching, these individuals would benefit by having their own specific exercise barriers and reinforcements identified, an end that can be achieved using psychological questionnaires or by careful interviewing. For persons who have been involved in a regular exercise program for several months or longer, the focus should be on renewing or redefining goals, in order to make active exercise a lifelong habit.
Anxiety and depressive disorders are major public health problems, and their costs to both the individual and the society are enormous. Unfortunately, many depressed and anxious individuals either receive inadequate treatment or none whatsoever, and the capacity for treatment falls short of the need. It is therefore of utmost importance to help people take active responsibility for their own health. Substantial mental health gains may be achieved by adopting a habit of regular exercise, and the potentials of exercise may be improved when exercise is integrated with cognitive behavioral theory.