Your brain on barbells: Can strength training improve your mood?

Exercise changed my life. It managed to do what medication alone couldn’t: put a dagger into my depression.

I’ve struggled with depressive illness since childhood, and throughout the years, my brain and body have often felt like a one-man clinical trial for every antidepressant that came to the market. Prozac? Been there! Luvox? Done that! Effexor? Check! Paxil, Wellbutrin, Lexapro, Zoloft? Check … check … check … and check-a-rooni!

Although mood-stabilizing pill packs have entered and exited my life with varying degrees of success over the past 30 years, one treatment option has remained a constant, reliable, no-fail mood booster throughout the decades. That would be exercise. But not just any exercise. Not the elliptical. Not spin class. Not the recumbent bike nor the rowing machine. In fact, it’s not aerobic exercise at all, which has been most commonly linked to a reduction in depressive illness.

It’s strength training—the muscle-building, body-toning and sometimes grunt-inducing workout—that has helped transform my chronic mental illness into better mental health. In fact, once I began a regular regimen of resistance training, the positive shift in my mood, my confidence and my self-image was so pronounced that I switched careers.

I left my work in the social service field to become a personal trainer and eventually a college professor of fitness and health promotion. Whether lecturing students, speaking to audiences or coaching clients, encouraging others to strength train for better mental health has become my mantra, my message and my life mission.

But I’m not basing this message on my firsthand experience alone. New research is validating what I feel every time I pump iron: peace of mind and a sense of achievement.

The impact of resistance training on emotional disorders is an emerging area of exercise science, according to Jacob Meyer, an assistant professor of kinesiology at Iowa State University. “Studies that explore the relationship between exercise and mental health have focused on aerobic activity for a couple of reasons,” he says. “From a research perspective, aerobic exercise is simpler, more straightforward and more easily quantifiable to study than resistance exercise. And historically, because ‘cardio’ is easily accessible and has been the exercise of choice for many people, it was more readily available to study than resistance training.”

With more people lifting weights and searching for non-pharmacological treatments for depression, however, interest is growing in studying the effects of resistance training.

Meyer was among the authors of a recent meta-analysis of the link between resistance training and depressive symptoms conducted by Brett Gordon, then a postgraduate researcher at the University of Limerick’s Department of Physical Education and Sport Sciences and now a postdoctoral fellow studying exercise and cancer at Penn State. The study, published in the June 2018 issue of JAMA Psychiatry, analyzed 33 clinical trials for the effects of resistance exercise on depression. Results showed that resistance exercise “significantly reduced depressive symptoms” among research participants.

One notable finding was that participants showed an improvement in their mood regardless of whether they grew physically stronger from the exercises. That means that triggering a mood boost may not depend on how many exercises you do or how hard you train. “Perhaps it might be the sense of accomplishment and confidence that comes from exercising, rather than the achievement of actual strength gains, to explain why study subjects felt better,” Meyer says.

Of course, feelings of pride and confidence that accompany the mastery of other physical activities, such as aerobic exercise, can also enhance mood. But Meyer believes that resistance training may create greater antidepressive benefits than other forms of exercise. “If the physiological adaptations associated with strength gains and muscle growth interact with the neurobiology of depression, then it may have different (and greater) effects on depression than aerobic training alone,” he says.

Resistance exercise doesn’t affect depression alone; research shows that it can reduce symptoms of anxiety, too. For a 2017 study published in the journal Sports Medicine, Gordon and his colleagues conducted another meta-analysis of 16 studies involving 992 total participants; it concluded that resistance training “significantly improves anxiety symptoms among both healthy participants and participants with a physical or mental illness.”

Matthew Herring, an author of both meta-analyses, says, “Evidence from studies of both animals and humans supports that resistance exercise training may improve both anxiety and depression by acting on those same neurobiological systems, particularly neurotransmitters and neurotrophic and growth factors.” More research, however, needs to be done, adds Herring, a lecturer in sport, exercise and performance psychology at the University of Limerick.

Resistance training, like other exercise, induces the release of a protein called BDNF, or brain-derived neurotrophic factor, into the hippocampus region of the brain. Among other functions, the hippocampus is responsible for mood regulation, and in people who are depressed, it shrinks up to 25% of its normal volume. The release of BDNF triggers the growth of new brain cells in the hippocampus, restoring it to its full size and improving communication between cells.

“That’s the physiological theory behind why you feel so good after working out,” says Jason Sawyer, an assistant professor of wellness and exercise science at Rhode Island College in Providence who has conducted small studies that found that weight training improved the mood of depressed college students. Although acknowledging that any degree of physical exertion will elicit a BDNF response, he says: “The purpose of my research is to give people options for alleviating feelings of depression. That’s why I focus on the lesser-studied resistance exercise.”

Sawyer and Meyer join Herring in calling for more research. “Of the 33 trials we evaluated for our study, only four required a diagnosis of depression as criteria for participation,” Meyer says. “We know there is a need for more investigation that narrows inclusion to only people with diagnosed depressive illness.”

For Sawyer, it’s not just academic; it’s personal. Like me, he lives with depressive illness. And like me, he pumps iron to manage his condition. “What motivates my work and research is my own experience as a weightlifter living with depressive illness,” he says. I’ve found lifting weights to be as effective at managing my symptoms as medication with zero side effects.”

If you’re new to strength training but would like to see whether it will bolster your mood, Sawyer suggests trying a 45-minute workout—including two sets of each exercise, with eight to 12 repetitions—two to three times per week.

Fitness and wellness educator and consultant Kimberlee Bethany Bonura recommends focusing on large muscle groups such as the legs and core muscles of the abdominals, pelvis and hips. “Exercises like squats, lunges and planks strengthen the core, which leads to better posture, and the research is showing that better posture promotes better mood,” she says. In fact, that’s how Sawyer and I both train: moving bigger muscles for bigger mood-boosting results.

Ready to begin? Check out the free online exercise resource called the American Council on Exercise, or ACE. (Go to the website acefitness.org and search “exercise library.”) The site offers a large collection of body-weight exercises that can be done at home for all levels and abilities.

-—-

Lorne Opler is an adjunct professor at Fleming College in Peterborough, Ontario, and a certified strength and conditioning specialist in Toronto.