Physical fitness in depressive patients and impact of illness course and disability

Abstract

Background There is a large and increasing body of evidence that physical exercise, such as endurance training, exerts antidepressant effects in psychiatric disorders. However, compliance rates are rather low due to reduced energy and lack of motivation. Another important reason may be low baseline fitness leading to overstrain when participating in a training program. The aim of the study was to evaluate the physical fitness of depressive patients compared to healthy controls by a standardized assessment. Methods 51 hospitalized depressive patients were investigated by a standardized physical fitness assessment on a bicycle ergometer including measurement of maximum workload (pmax), heart rate, lactate concentration, workload at first lactate elevation (pLT), individual anaerobic threshold (IAT) and workload at IAT (pIAT). They were compared to 51 healthy controls matched for age, sex and body mass index. Results p(max), p(LT) and p(IAT) were markedly reduced in depressive patients compared to healthy controls ( p < 0.001). Lactate increase was faster and steeper in depressed patients, albeit differences never reached significant levels. There was a significant negative correlation between the length of disability and poor performance parameters but no significant correlation with other illness variables. Limitations The study was not prospective and no study protocol was applied. Conclusion This study demonstrates a marked reduction of physical fitness in depressive patients which cannot be explained by differences of body mass index or age. When designing therapeutic exercise programs for depressive patients evaluation of baseline training level is recommendable because many patients might overstrain themselves because of strongly reduced baseline fitness.