Although past research shows that exercise improves chronic health conditions, such as diabetes and heart disease, it also shows that patients with diabetes and heart disease often suffer from depression. New research indicated that people suffering from depression are less likely to exercise; a key prescription to improve these health conditions.
The analysis evaluated 11 studies comprising some 20,000 patients. Eight studies reported that having symptoms of depression after a coronary event, such as heart attack, was a significant risk factor for developing a sedentary (less active) lifestyle or a poor adherence to an exercise program recommended by the patients' doctor.
One study, for example, investigated the role of depression and anxiety in 224 heart attack survivors, at three months and 12 months after their hospitalization. Of those with anxiety and depression during hospitalization, 59 percent had a significant decrease in exercise after three months, compared with 31 percent of those who were not depressed. A year later the gap widened, with 51 percent of depressed patients exercising less compared with 26 percent of non-depressed patients.
The studies used different methods to measure depression and physical activity and there was a great difference in how they compared factors such as the patients' health, physical activity and depression.
There are many suggested theories to explain why depression leads to a decline in activity. Babak Roshanaei-Moghaddam, M.D. of the department of psychiatry and behavioral sciences at University of Washington in Seattle and lead author of the study offered one theory.
"We have hypothesized that there are both behavioral habits associated with depression, such as smoking and obesity, which may then limit exercise motivation and enjoyment, as well as biologic factors that can cause obesity and decrease energy level, exercise tolerance and pain threshold," he said.