Benefits of exercises on depression

In recent years, several publications have reported positive effects of physical activity on mood. However, the validity of 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.3, 4 In some studies, exercise programmes were started or carried out at the same time as pharmacological treatment or psychotherapy.5, 6 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 psychotherapy7, 8 and more effective than other behavioural interventions8 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.3 In a recent study,9 resistance training over 10 weeks was more effective than a placebo activity to reduce depression scores in elderly people with a Beck Depression Inventory Score >12. Finally, in a further study, 40 clinically depressed women carried out one of two exercise programmes (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.10

This evidence supports the need for further investigation of the effects of physical activity on patients with more severe forms of affective disorders. Indeed, exercise could have several advantages as treatment for depression—for example, low cost, associated positive effects on physical performance and cardiovascular risk, absence of secondary effects, and potential prevention of future episodes. In a previous study on the effect of an exercise programme on the physical performance of patients after bone marrow transplantation, we observed a substantial improvement in the mood of participants after a few days.11 Furthermore, a meta-analysis has shown that even a single exercise bout can improve mood.7 In view of these findings, we carried out a pilot study to evaluate the effects of a short term aerobic training programme on patients with major depression.

Patients and methods
A successive series of inpatients and outpatients with major depression were considered for participation in the study. All patients had been diagnosed as suffering from major depressive disorder according to DSM IV criteria. Further inclusion criteria were age between 20 and 65 years, no change in treatment (psychotropic medication, psychotherapy or behavioural therapy) in the six weeks preceding the training programme, hospitalization for at least two weeks without improvement (for hospitalized patients only), a score of 15 or more on the Hamilton Rating Scale for Depression (HAMD, 21 item version), absence of associated organic disease or schizophrenic symptoms, and ability to understand written German. The study was approved by the institutional ethics committee.

A total of 12 patients who fulfilled the inclusion criteria were asked to participate (table 1); all patients gave written informed consent and were recruited for the study. The duration of the present depressive episode was 35 (21) weeks (range 12–96). Ten patients suffered from refractory depression, defined as a lack of improvement after treatment with at least two antidepressants with different mechanisms of action at adequate dosage (tricyclic antidepressants ≥150 mg/day, serotonin reuptake inhibitors ≥20 mg/day) for at least four weeks during the present episode.