New research that objectively monitored the movement of depressed patients provides evidence that moderate — but not light — intensity physical activity is associated with reduced depressive symptoms. The findings have been published in the journal Psychiatry Research.

Dr. Ioannis D. Morres, the lead author of this study, reports:

Although exercise is a type of physical activity with well-established antidepressant effects in clinical settings, depressed outpatients may often dropout from community-based exercise programs. A potential explanation suggests depressed patients may find exercise too taxing, as it is planned, repetitive, structured and purposive, and needs to be group-based and supervised according to guidelines for depression treatment.

According to The World Health Organization (2011), however, reports that exercise is not necessarily the only type of physical activity linked to lower depression. Particularly, the WHO guidelines report that various physical activity subsets (e.g., walking, cycling or sports) across different daily life domains (e.g., work, house or leisure) are linked to lower risk for depression when performed ≥30minutes/day for ≥5times/week at moderate intensity (in moderate intensity your heart will beat faster and you will breath harder than normal, but you will still be able to talk).

In line with WHO guidelines, a number of studies suggest daily life physical activity subsets including cycling, walks or long hikes are associated with reduced depression severity; importantly, these subsets do not carry the potentially taxing characteristics of exercise (e.g., planned, supervised or group-based).

But the promising evidence for the antidepressant links of physical activity subsets is typically derived from subjective (self-report) measures. Subjective measures may often record inaccurate information due to poor concentration and memory skills of depressed patients. Hence, a number of studies reporting a lack of an association between subjectively measured physical activity and mental health are unsurprising and potentially confusing.

To provide relevant clarifications, we explored if objectively rather than subjectively measured physical activity in daily life is linked to lower depression in clinically diagnosed major depressed outpatients (18-65 years) with no suicide ideation. This target group was selected because it is the most prevalent treatment group in community mental health services.

Health professionals (responsible for patients’ treatment) referred eligible patients to our study. Nineteen patients were asked to wear hip-worn triaxial accelerometer devices for 7 consecutive days (apart from bathing/sleeping hours) in order to objectively record physical activity. Accelerometers are small (3.8cm x 3.7cm x 1.8cm) and light (27gr) devices with an elastic belt. Patients were advised to avoid lifestyle modifications during participation in the study. Upon the return of accelerometers in day-8, the severity of depression for the last 7 days was also assessed.

Our mild-moderate major depressed outpatients recorded 31.19 minutes of daily moderate intensity physical activity in everyday living. This amount of moderate intensity physical activity was related with lower depression. Light intensity physical activity was not related with depression.

Our study suggests that approximately 30 minutes of moderate intensity physical activity in the daily life of mild-moderate major depressed outpatients appears to be an important contributor to lower depression severity.

There are three caveats, which concern the interpretation of our findings. First, the contribution of domain-specific physical activity (e.g., transport to work, house or leisure activities, etc) or type-specific physical activity (e.g., walking, long hikes, household, etc) to lower depression was not examined.

Second, we did not employ non-depressed controls to examine for differences vs. major depressed outpatients.

Third, we did not monitor if our major depressed outpatients were motivated towards increased physical activity as a result of their participation in the study. Researchers need to explore the contribution of domain- and type-specific physical activity to depression while examining for between group differences and controlling for motivation confounding effects.

In support of future research, it is encouraging to note that 70% of eligible patients participated in our study and showed a high valid wear time of the accelerometer devices; also, only one participant (5%) dropped out (due to personal reasons). Our study was conducted under the aegis of the Exercise Psychology & Quality of Life Laboratory of the Physical Education and Sport Science Department at the University of Thessaly (Trikala, Greece) in collaboration with the Vyronas/Kaisariani Community Mental Health Centre, School of Medicine, National-Kapodistrian University of Athens (Athens, Greece).

Finally, we would also like to note another recent study from our lab, published in Depression and Anxiety. Our study was a meta-analysis that synthesized the findings from a number of experimental studies on the impact of aerobic exercise in depressed adults. The results from this review showed large antidepressant effects for aerobic exercise vs. psychotherapy, antidepressant

medication or treatment as usual.

The National Institute of Health Research (NIHR) Dissemination Centre has highlighted this study as a Signal for its high quality design and relevance to decision makers in the United Kingdom.

Projects related to physical activity and mental health can be found at the homepage of the Laboratory of Exercise Psychology and Quality of Life of the Physical Education and Sport Science Department, University of Thessaly, Trikala, Greece.

The new study, “Objectively measured physical activity and depressive symptoms in adult outpatients diagnosed with major depression. Clinical perspectives“, was authored by Ioannis D. Morres, Antonis Hatzigeorgiadis, Charalampos Krommidas, Nikos Comoutos, Eirhini Sideri, Dimitrios Ploumpidis, Marina Economou, Athanasios Papaioannou, and Yannis Theodorakis.