Exercise, Meditation a Double Threat for Major Depression

Nancy A. Melville

February 18, 2016

A combination of aerobic exercise and focused-attention meditation performed twice weekly significantly improves symptoms of major depressive disorder (MDD) after just 8 weeks, new research shows.

"[We found that] combining these two important behaviors into people's lives might be particularly beneficial," lead author Brandon Alderman, PhD, assistant professor in the Department of Exercise Science at Rutgers University, New Brunswick, New Jersey, told Medscape Medical News.

"The data show meaningful improvements in cognitive function and symptoms of depression," he added.

Meditation and exercise are both commonly recommended for the treatment of depression. However, there have been no studies of the benefits of the two measures combined as a structured intervention, the authors report.

The study was published online February 2 in Translational Psychiatry.

Significant Symptom Reduction

For the study, the investigators enrolled 52 participants in Rutgers' counseling and psychiatric services clinic, including 22 with a diagnosis of nonpsychotic MDD (5 men, 17 women) and 30 healthy control participants (10 men, 20 women) who had no diagnosis of MDD and no previous or current history of neuropsychiatric disorders or head injuries.

All participants received the intervention, dubbed mental and physical (MAP) training. The regimen consisted of two sessions per week, beginning with 30 minutes of the focused-attention mediation followed by 30 minutes of aerobic exercise.

After the 8-week intervention, patients with MDD were found to have a significant reduction in depressive symptoms, as assessed on the basis of self-reported measures on the Beck Depression Inventory–II (BDI-II), as well improvement in overall rumination measures, compared with baseline and with healthy control particpants (both P < .001).

In addition to the psychological improvements, increases in synchronized neural activity, measured with the recording of event-related brain potentials (ERPs) on electroencephalogram (EEG) during cognitive control tasks, were also observed following the intervention. Specifically, increases were seen in measures of N2 and P3 component amplitudes compared with baseline in participants with MDD (both P < .001).

In a previous study, Dr Alderman's team found that those with MDD had reductions of the same N2 component.

"These ERPs have previously been used to reflect neural activity during conflict monitoring and cognitive control," the authors note.

Increased, Sustained Neurogenesis

The findings support the authors' theory of a mechanism in which exercise and meditation work together to increase and sustain neurogenesis.

"Collectively, these findings suggest that aerobic exercise increases the production of new neurons in the adult brain, while effortful mental training experiences keep a significant number of those cells alive," they write.

The MAP intervention starts with participants sitting in silence in a cross-legged or other comfortable, upright position. While in this position, they are instructed to focus their attention on their breathing and to count each breath if necessary to maintain focus.

If attention during the meditation drifts to thoughts about the past or the future, participants are instructed to acknowledge the shift and return their attention to the breath. Following 20 minutes of the sitting meditation, participants stand and engage in 10 more minutes of slow-walking meditation, focusing their attention on their feet.

Following the 30-minute meditation session, participants perform aerobic exercise of moderate intensity for another 30 minutes. This involves a 5-minute warm-up followed by exercise on either a treadmill or cycle ergometer, with heart rate intensity corresponding to 50% to 70% VO2 peak, set according to individual baseline fitness assessment.

Positive Impact

Dr Alderman noted that despite the encouraging findings, an important consideration regards how long patients are able to sustain the intervention and the benefits.

"A critical question that remains is the extent to which participants really value meditation and exercise and integrate these behaviors into their lives," he said.

"This is a difficult issue related to behavioral adherence, motivation, and other complex factors, but something we're absolutely interested in assessing in future studies," Dr Alderman added.

In a previous study that examined the effects of exercise on depression, benefits were found to persist, and participants had lower relapse rates than occurred with antidepressant therapy. However, he noted, in that study, the exercise regimen continued for a longer period (more than 10 months).

"The optimal dose and our understanding of how the combination of exercise and meditation particularly impact depression and/or depressive symptoms remain unknown — and to be tested," he said.

He noted that even participants in the group that did not have MDD reported improvements in mood with the intervention. Among those with MDD, one anecdotal report was especially encouraging.

"One clinically depressed participant mentioned that the intervention saved her life," Dr Alderman said.

"That's a powerful statement, and although I'm not a qualitative researcher and don't often deal with anecdotes, it's hard to look past such a positive sentiment."

Remaining Questions

Although the study adds to previous findings showing benefits of regular meditation practices and physical exercise on depression, it has important limitations, commented Stefan G. Hofmann, PhD, who is director of the Psychotherapy and Emotion Research Laboratory in the Department of Psychology at Boston University.

"The most interesting aspect of the study is the EEG result during the cognitive control task," he told Medscape Medical News.

"However, the lack of a control group is a significant limitation. The placebo effect is very strong in [these types of] studies," he said. "Furthermore, it is unclear which component of treatment is most effective and what the mechanism was."

Another important limitation was that the effect of cognitive-behavioral therapy (CBT), which is currently the most common treatment for depression and is considered to be the most effective, was not included in the study, Dr Hofmann noted.

"Modern CBT includes mindfulness practices and behavioral activation," he said. "In addition, it examines maladaptive thinking patterns and dysregulated emotional responses. All of these components are effective interventions."

The study received funding from the Charles and Johanna Busch Memorial Fund, at Rutgers University, and the Brain and Behavior Research Foundation. The authors and Dr Hofmann have disclosed no relevant financial relationships.

Transl Psychiatry. Published online February 2, 2016. Full text

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