Depression is one of the most prevalent psychological
disorders and results in reduced quality of life and productivity.
Major depressive disorder involves decreased
activity, reduced social connections, negative thoughts
about oneself (i.e., feelings of guilt or worthlessness),
and various physiological changes, including fatigue or
restlessness and changes in appetite and weight
(American Psychiatric Association, 2013). Standard
treatments include behavioral activation, cognitive therapy,
other psychotherapies, and psychotropic medications.
Exercise has been proposed and investigated as
an alternative treatment.
One reason for the appeal of exercise is the opportunity
for behavioral activation and social contact it can
provide. Such engagement could create opportunities
for positive reinforcement, otherwise diminished in
depression (Lewinsohn, 1974). Additionally, engaging
in exercise may alter a person’s thoughts and enhance
self-esteem. Many proponents of exercise interventions,
however, have highlighted alterations in physiological
and neurotransmitter functioning although the consequences
of these changes remain poorly understood
(Heijnen, Hommel, Kibele, & Colzato, 2016). While it
does pose modest risks for injury in those who are not
fit, exercise has also been associated with secondary
health benefits, such as improved cardiovascular functioning
(Riebe et al., 2015).
Cooney, Dwan, and Mead (2014) conducted a metaanalysis
investigating the therapeutic effects of exercise
for depression, as well as comparative differences
among exercise, psychotherapy, and psychotropic medication.
Their findings indicated that exercise has a
small to moderate effect size as compared to control
intervention or placebo. Analysis of the small number
of studies comparing exercise to existing evidencebased
therapies revealed that it was no more effective
than established treatments. Review of all 35 studies
showed significant variability in treatment adherence
rates ranging from 50% to 100%, though the authors
noted that 29 studies described the treatment as acceptable.
The meta-analysis also reported moderate heterogeneity
in the findings for exercise, though subsequent
analyses have attributed this variability to differences in
the control conditions across trials. Tai chi, yoga, qigong,
and similar practices were not included as exercise
interventions, while some control conditions
included yoga and other activities that might be reasonably
construed as exercise (Ekkekakis, 2015).
While findings for exercise-based interventions show
promise, there is insufficient evidence at this time to pinpoint
the type, intensity, dose, or frequency of exercise
that may be most effective for treatment of depression.
Standard prescriptions have included 30 minutes per day
of brisk walking or similar low-impact activity, but clinicians
considering such an intervention are advised to
consider the overall health of clients before prescribing
(Currie & Malik, 2016). Additionally, there is insufficient
research to identify particular client groups and
comorbidities for which exercise may provide a more
effective therapy than established treatments.
