Exercise intensity and major depression: results of a preliminary study

Background Depression is a complex disorder characterized by depressed mood, loss of interest or pleasure in activities, low self-worth, low energy and poor concentration. Depression is one of the most common psychiatric disorders, affecting about 121 million people worldwide (WHO, 2010), is the leading cause of disability measured by YLDs and the 2nd cause of DALYs in the age 15-44 for both sexes and are expected to show a rising trend during the coming 10 years (Lopez et al., 2006). Exercise has been recognized as a potentially effective treatment for depression. Literature has been significantly growing in the last 20 years, with results of RCTs indicate that participation in physical activity programs reduces depression symptoms (Daley, 2008; Krogh et al. 2010; Perraton et al., 2009;). Exercise can be a good option which has few negative side effects and could be cost-effective in comparison to both drug and non-drug options. Purpose This preliminary study was designed to test the response of two different exercise intensity in depressive symptoms measured with Hamilton Rating Scale for Depression (HRSD). Setting/participants Exercise was performed in a supervised clinical setting by 20 inpatients of both genders (mean age 47.4, SD ±9.8), diagnosed with major depression according to DSM-IV-TR. Patients received antidepressant medications in accordance with international recommendations. Intervention Participants were randomized in two exercise groups (high intensity -5 METs- or low intensity -3 METs-), performing 1 hour of exercise/day, 5days/week in 4 consecutive weeks. Results HRSD mean scores at 4 weeks were significantly reduced from baseline (t -9.8, p < .001), with no significant differences between the two groups. Conclusion Differently from previous studies (Dunn et al., 2005), in the present trial exercise intensity did not appear a determinant factor to reduce depressive symptoms, with results of higher intensity group that were similar to those of lower.