If you read these pages often, you might come to think that exercise is a cure for everything. Along these lines, a new study has examined the use of endurance (aerobic) exercise in treating older persons with depression. Depression in the elderly is quite common - it is reported in 5% to 10% of community elders, rising to 18% in nursing home residents. Moreover, depression is associated with an increase to death rate that is not due to suicide (see this article).

Antidepressant drugs are quite successful in treating depression in the elderly, but they can have unpleasant side effects that may stop patients using them. A good alternative to drugs would therefore be useful. The study we summarize here compared results in 3 groups - one having a course of aerobic exercise, one having drug treatment, and one having a combination of exercise and drug treatment.

Participants were recruited by advertisements and through their family physicians or mental health centers. At entry, they took a rating scale for depression (part of the Hamilton rating scale - the HAM-D) and completed a questionnaire called the Beck Depression Inventory (BDI). Patients already taking antidepressants or other medications were excluded, as well as any that could not undertake the exercise program (e.g. those with heart, respiratory or orthopedic problems).

The exercise treatment consisted of 30 minutes of continuous walking or jogging (with 10- minute warm-up and 5-minute cool down periods) at a rate to provide 70% to 85% of the heart rate reserve. The sessions were done three times a week for 16 consecutive weeks. Patients on medication received sertraline, one of the newer types of antidepressants, at a dose of 50 mg, increased up to 200 mg if necessary to produce the desired effect. At the end of 16 weeks the patients had their symptoms reassessed using the HAM-D and BDI scales.

Over 150 patients took part in the study, distributed equally between the three treatment groups. Their ages ranged from 50 to 77 - the average age was 57 years. Although 30 participants dropped out before the end of the study, there were no differences between the groups regarding the drop-out rate, or indeed any of the particulars gathered - gender, level of education, marital status, income, ethnic background, or history of previous depression.

All three treatment groups showed significant reductions in their depressive symptoms after 16 weeks. The percentage of patients classified as clinically free of depression in each treatment group was almost the same - 60.4%, 68.8% and 65.5% respectively. The only difference between groups was that the rate of response was faster in the persons getting medication alone; they responded more rapidly over the first few weeks. Mildly depressed patients responded more quickly to the combination of medication and exercise than did more severely depressed patients.

This study shows that aerobic exercise is a practical alternative to medication in elderly patients with depression. The numbers of people not completing treatment were the same for exercise and medication, and there was a slight but important improvement in exercise capability in those patients who exercised. The actual size of the beneficial effect in each group was the same as in other studies using this drug, or when other effective non-drug treatments are given (e.g. behavioral or psychosocial treatment).

The reason for the favorable effects of exercise is uncertain. It may be that their improved levels of fitness made people feel better in themselves. It may be that the physiological effects of exercise improve mood or self-esteem in some biochemical way (e.g. by release of endorphins). One important point is the social interaction that occurs in exercise regimens; to be sure that it is the exercise itself that is beneficial, one would have to do another study with the subjects exercising alone at home.

Before we attach too much importance to this study, we should remember that it was relatively short, and therefore doesn't provide much information about the possible return of depressive symptoms. Recurrences are often reported in over half of older patients. Nevertheless, the findings are encouraging for those elderly people with depression who cannot tolerate antidepressant drugs, or who require the benefits of a social activity that in itself carries numerous other rewards. It looks as if depression can be added to the growing list of conditions where we can say with certainty "Exercise is good for you".