Resistance exercise training associated with reduced depressive symptoms in young adults

Young adults who participated in a resistance exercise training program saw significant reductions in depressive symptoms, according to a new study published in the journal Psychiatric Research. The study results are particularly noteworthy because they indicate that even relatively brief participation in resistance training can lead to noticeable improvements in mood for both men and women.

Traditional treatments for depression, such as antidepressant medications and psychotherapy, have their limitations, including variable effectiveness, side effects, and issues related to cost and accessibility. Therefore, there is an urgent need to explore alternative and complementary treatment options, especially for individuals experiencing mild to moderate depressive symptoms.

Previous studies have established the potential antidepressant effects of exercise, but most of these investigations have focused primarily on aerobic physical training. Resistance training, a less explored path in this context, is a form of exercise that involves activities such as weight lifting, which aims to increase muscular strength.

“The antidepressant effects of exercise are well documented and most interventions have used aerobic exercise,” explained study author Darragh OSullivan, a PhD student at the University of Limerick. “Previous meta-analytic evidence has shown that resistance exercise training also reduces depressive symptoms; however, evidence is lacking among young adults. Approximately 37% of depression cases develop before the age of 25.”

“Generalized Anxiety Disorder also typically develops in young adulthood and is highly comorbid with Major Depressive Disorder. Consequently, young adults, especially those with anxiety, are at risk for depression. Our laboratory is currently investigating the appropriateness of resistance exercise training as an alternative or augmentative treatment for anxiety and depressive symptoms among young adults with and without Generalized Anxiety Disorder and clinically significant Major Depressive Disorder.”

For their new study, the researchers analyzed existing data from two parallel randomized controlled trials. These trials were designed to investigate the effects of resistance exercise training on anxiety symptoms in young adults.

The sample included 55 young adults. To be eligible, participants needed to meet specific criteria, including being between the ages of 18 and 40, not having medical conditions that would contraindicate participation in resistance training, and not being pregnant or breastfeeding.

These participants were randomly assigned to either a resistance training program or a wait-list control condition. The resistance training program followed the recommendations of competent bodies such as the World Health Organization (WHO) and the American College of Sports Medicine (ACSM). The program included eight different exercises, including barbell back squats, barbell bench presses, hex bar deadlifts, seated dumbbell lat raises, barbell bent over rows, dumbbell lunges, seated dumbbell curls, and abdominal crunches.

Participants went through a three-week familiarization process before the official start of the program to ensure they were using the correct lifting techniques and resistance levels were appropriate. Twice-weekly exercise sessions lasted approximately 25 minutes and were fully supervised by trained personnel.

Participants in the control group did not participate in the resistance training program, but completed online questionnaires weekly. They were offered the opportunity to participate in the resistance training program intervention after completing their waitlist status, but no data were collected during this phase.

Participants attended an average of 83% of the sessions and had an 80% adherence rate, indicating strong engagement with the program. It is important to highlight that there were no adverse events related to resistance training, demonstrating that it was viable and well tolerated.

The researchers found that resistance training significantly reduced depressive symptoms in the total sample of young adults, both among individuals with Major Depressive Disorder and among individuals with clinically significant symptoms of Generalized Anxiety Disorder. This effect was consistent across male and female participants.

At baseline, participants had mild depressive symptoms, and the resistance training intervention led to a clinically significant reduction in depressive symptoms. The effect size of the reduction was large (d = 1.01), indicating a substantial improvement. The antidepressant effect was most pronounced between weeks one and four.

“Eight weeks of resistance exercise training based on WHO and ACSM guidelines, with two sets of 8 to 12 repetitions of eight simple exercises, can induce large, clinically significant reductions in depressive symptoms among young adults,” O’Sullivan told PsyPost.

“The antidepressant benefits of engaging in resistance exercise may plateau after initial improvements but may continue with additional training. Most young adults with at least mild depression can benefit from resistance exercise training; In the current sample, 18 of 19 participants (95%) who met criteria for at least mild depression at baseline no longer met these criteria by week eight.”

Participants also experienced a significant increase in strength during the intervention. But changes in strength were not significantly associated with changes in depressive symptoms. This suggests that the antidepressant benefits of resistance training may not necessarily depend on increasing physical strength, but rather on other mechanisms.

“Reductions in anxiety symptoms were also found in the current study, suggesting that resistance exercise training may simultaneously reduce depressive and anxiety symptoms among young adults with and without clinically significant anxiety,” O’Sullivan noted.

But the study, like all research, has some limitations.

“The resistance exercise sessions were fully supervised, individually, and consequently were not fully representative of real-world, unsupervised training,” explained O’Sullivan. “Still, extraneous conversations were minimized and scripted conversations were used to control for non-exercise benefits of the intervention, including social contact. There was no post-intervention follow-up. Longer-term follow-ups are needed to examine whether reductions in depressive symptoms are maintained after intervention.”

The study, “Effects of Resistance Exercise Training on Depressive Symptoms Among Young Adults: A Randomized Controlled Trial,” was authored by Darragh OSullivan, Brett R. Gordon, Mark Lyons, Jacob D. Meyer, and Matthew P. Herring.