Aerobic Exercise Augments PTSD Therapy

Batya Swift Yasgur, MA, LSW

December 06, 2022

A brief aerobic exercise intervention can augment the benefits of exposure therapy for posttraumatic stress disorder (PTSD), new research suggests.

Investigators randomly assigned individuals with PTSD to receive either exposure therapy with aerobic exercise or exposure therapy with passive stretching for 9 weeks. At 6 months post-intervention, participants in the aerobic exercise group showed greater reductions in PTSD severity, compared with those in the stretching group.

"There is a critical need to improve outcomes for treating people with PTSD, and this finding points to one potentially cheap and ready-to-use strategy that all clinicians could employ with most patients," lead author Richard Bryant, MPsych, PhD, DSc, director of the Traumatic Stress Clinic and Scientia Professor of Psychology at the University of New South Wales, Sydney, Australia, told Medscape Medical News.

The study was published online November 24 in Lancet Psychiatry.

Promoting BDNF

"Trauma-focused psychotherapy is the recommended treatment for PTSD, but up to half of patients do not respond to this treatment," Bryant said.

"We know that brain-derived neurotrophic factors (BDNF) are critical for synaptic plasticity, which underpins the learning that occurs in therapy so that reminders of trauma are no longer fear-provoking," he continued. "Preclinical animal and human research inform us that brief aerobic exercise can promote BDNF and new learning that inhibits fear responses."

The researchers "hypothesized that brief exercise after exposure therapy to trauma memories — which is the key ingredient of trauma-focused psychotherapy — would lead to greater reductions in PTSD, relative to standard trauma-focused therapy," he said.

To investigate the question, the researchers randomly assigned 130 adults with PTSD (mean age 39 years, 61% female, 76% White) to receive nine 90-minute sessions of exposure therapy with either aerobic exercise or passive stretching (n = 65 in each group).

There were no differences at baseline in sociodemographic characteristics or psychopathology measures, although the mean age of the stretching group was slightly older than that of the aerobic group (40 years vs 37 years, respectively), and there was a slightly higher proportion of women in the stretching group (68% vs 54%).

Participants did not differ on weekly exercise either at baseline, immediately posttreatment, or at 6-week follow-up.

PTSD severity (the primary outcome) was measured using the clinician-administered PTSD scale CAPS-2, with assessments conducted at baseline, 1 week posttreatment, and 6 months posttreatment.

The aerobic exercise regimen was tailored to each participant, based on an assessment of his/her aerobic target zone.

The exposure therapy sessions were identical for both groups. Following the exposure sessions, participants engaged in their respective exercises: those in the passive stretching group engaged in 20 minutes of exercise, while those in the aerobic group participated in a total of 20 minutes of exercise, with 10 conducted at their personal aerobic target heart rate.

"This level of exercise was chosen because BDNF concentration in the serum is increased by two 3-minute bouts of aerobic exercise, and 10 minutes of aerobic exercise can facilitate extinction learning," the authors explain.

The aerobic activity consisted of running on a stepper exercise platform while having cardiac activity recorded.A small portion (10%) of the therapy sessions were recorded and rated for treatment fidelity.

Change in PTSD was the primary outcome, with secondary outcomes consisting of changes in depression, anxiety, alcohol use disorder, and posttraumatic cognitions.

Few Barriers

The researchers found no significant differences in PTSD severity, as measured by CAPS-2 score, between treatment groups at 10 weeks — ie, immediately posttreatment (mean difference 7.0 [95% CI, -2.3 to 16.4]; P = .14).

However, significantly greater reductions in PTSD severity were found in the aerobic vs the stretching group at 6-month follow-up (mean difference 12.1 [95% CI, 2.4 - 21.8]; P = .023), pointing to a "moderate effect size" (d = .6 [.1 - 1.1]).

Although there were no differences found at 6-month assessment between rates of PTSD diagnosis (25% of the aerobic vs 27% of the stretching group), more participants in the aerobic group reached a "minimal clinically important difference," compared to those in the stretching group (96% vs 84%, respectively, χ² = 4.4; P = .036). 

There were also superior benefits found in the aerobic vs the stretching group on depression severity at 6 months (a secondary outcome), with a mean difference in Beck Depression Inventory-2 (BDI-2) score of 5.7 (95% CI, 0.5 - 10.9; P = .022), yielding a "moderate effect size" (0.5 [95% CI, 0.1 - 1.0]).

There were no adverse events associated with the intervention, and almost all the sessions (88%) complied with the treatment protocol.

The researchers note several limitations. For example, they did not obtain plasma to measure BDNF concentrations, so they could not "infer whether the mechanism of change involved BDNF."

Additionally, they did not perform sex-specific analyses. "Future studies could increase the sample size to investigate sex differences because females display less BDNF change following exercise than do males," they write.

Nevertheless, the study "provides initial evidence of a simple and accessible strategy that clinicians could readily apply in combination with exposure therapy," they state.

"Whereas many pharmacologic interventions pose barriers, including cost, requirement for prescriptions, and patient resistance to drugs, exercise offers clinicians a strategy that can be implemented with few barriers."

Bryant emphasized that one study "does not represent a body of evidence, and so it is essential that this finding be replicated in other trials before it can be recommended for clinical use." He noted that other trials are "currently underway."

Easy Augmentation

Commenting for Medscape Medical News, Barbara Rothbaum, PhD, professor in psychiatry and director of the Trauma and Anxiety Recovery Program at Emory University School of Medicine, Atlanta, Georgia, called it a "well-controlled trial augmenting exposure therapy for PTSD with brief aerobic exercise and finding some benefits of the augmented condition at 6 months posttreatment but not immediately posttreatment."

The study's methodology — ie, using independent standard assessment of PTSD and rating audio recordings of therapy sessions for treatment fidelity and quality — can lead us to "be confident in their [the researchers'] conclusions," she said.

Rothbaum, who was not associated with this study, described research into methods to augment exposure therapy for PTSD as "timely and clinically relevant."

Exercise "would be an easy augmentation for many clinicians if it is helpful," she noted.

The study was funded by the Australian National Health and Medical Research Council. The authors and Rothbaum report no relevant financial relationships.

Lancet Psychiatr. Published online November 24, 2022. Abstract

Batya Swift Yasgur, MA, LSW is a freelance writer with a counseling practice in Teaneck, New Jersey. She is a regular contributor to numerous medical publications, including Medscape and WebMD, and is the author of several consumer-oriented health books as well as Behind the Burqa: Our Lives in Afghanistan and How We Escaped to Freedom (the memoir of two brave Afghan sisters who told her their story).

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