Fitness enthusiasts and athletes usually recognize the importance of strength training. The benefits to athletic performance are now common knowledge.
However, it still doesn’t get the credit it deserves in the general public, or even the healthcare community.
Fortunately, new research continues to demonstrate how strengthening exercise can be just as important for health and fitness as ‘cardio’. This can be reviewed in detail in the article: Why Strength Training is Important.
People usually think of these benefits in terms of physical health. But what people don’t realize is that strength training can be beneficial for mental health as well.
There is now good evidence (presented in an excellent review article published in 2010) that strength training alone can be beneficial for a variety of mental health issues (anything affecting the brain, really) such as anxiety, depression, chronic pain (low back, osteoarthritis, and fibromyalgia), cognition, symptoms of fatigue, self-esteem, and sleep, to name just a few.
Let’s discuss these effects, as well as some plausible mechanisms, by going over the previously mentioned review article.
‘Mental Health Benefits of Strength Training in Adults’
In 2010, a review article huh? written by Patrick J. O’Connor Ph.D., Matthew P. Herring M.S., and Amanda Caravalho was published in the American Journal of Lifestyle Medicine titled ‘Mental Health Benefits of Strength Training in Adults’. 1
The authors went through numerous research studies that investigated the effects of strength training on a variety of mental health issues. In the end they discussed a few plausible mechanisms by which strength training could affect mental health.
Let’s go over some of the interesting things they found:
- They had difficulty finding a lot of high quality research on strength training alone for mental health issues. Typically, studies on mental health and exercise use ‘general exercise’ which usually refers to moderate intensity ‘cardio’. Strength training has been generally neglected.
- Of the studies that used strength training, the programs typically reflected the recommendations of the American College of Sports Medicine for progressive resistance training. To review the parameters of such a program, click here.
- Strength training resulted in moderate reductions in anxiety in healthy adults.
- Only small improvements were found in people with an anxiety disorder. This suggests strength training affects something different than whatever causes an anxiety disorder. Interesting!
- Moderate intensity strength training (50-60% 1RM = 1.00 SD effect) seems to be more effective than high intensity strength training (80% 1RM = 0.71 SD effect).
- Low Back Pain
- Exercise in general reduces low back pain roughly 6-10 points on a 100 point scale. Not a slam-dunk… but for chronic low back pain, nothing seems to be – so this is actually quite good.
- Strength training alone has been shown to reduce pain to a moderate amount, and is just as effective as aerobic exercise (i.e. ‘cardio’).
- In people with chronic back pain, strength training is the best type of exercise for improving physical function.
- Strength training alone has moderate to large effects on chronic hip and knee osteoarthritis pain (up to 1.39 SD).
- It seems to be slightly (but not statistically significant) better than aerobic (walking), or combined strength + aerobic programs.
- This is probably why strength training is recommended as an osteoarthritis treatment by the American College of Rheumatology, American Geriatric Society, and the Centers for Disease Control and Prevention. Big name drops!
- Trials have found that strength training is just as effective as aerobic training for pain in fibromyalgia patients, with moderate to large effects (from <0.80 up to >2.00 SD)
- Strength training was shown to be superior to flexibility training in one trial (0.75 vs 0.49 SD) for fibromyalgia pain symptoms. No surprise.
‘Cognition’ refers to such things as memory, information processing, problem solving, and executive functioning – I guess you could call it “brain power” (I know… that’s super cheesy).
- Exercise in general has shown to improve cognition in older adults (who are the subjects of most of this type of research). Aerobic + strength is slightly better than aerobic alone.
- Strength training alone has low to moderate effects on cognition in older adults.
- The greatest improvements with strength training appear to be in memory tasks.
- Exercise of any type is effective at reducing symptoms of depression in people who are diagnosed as depressed.
- Strength training alone has been shown to be effective, with improvements being considered large and clinically significant.
- It seems not to work so well in depressed older adults, or depressed cancer patients.
- It seems highly effective in depressed ‘healthy’ adults and college students, and moderately effective in depressed people with fibromyalgia, osteoarthritis, or spinal cord injuries.
Perhaps the effectiveness of strength training for symptoms of depression depends on why you are depressed – an interesting caveat.
- Exercise of any type seems to improve symptoms of fatigue by a low to moderate (0.37 SD) effect – which is clinically meaningful and apparently better than “cognitive-behavioral or drug treatments”.
- Strength training alone resulted in the greatest improvements, which was true for many different groups, including fibromyalgia and cancer patients.
- Strength training is as good as aerobic training in improving general self-esteem, both having small effects (0.26 vs 0.25 SD).
- Research and theory suggests that these improvements in general / global self-esteem seem to be due to improvements in more narrow self esteem factors, such as ‘physical self-efficacy’ and ‘physical self-worth’ – which probably explains why exercise has a small effect (self esteem is built on many factors, and strength training effects only a few).
- Generally, people who exercise are less likely to develop sleep disorders.
- People who have depression can get up to 30% better sleep quality after a 10 week strength training program.
- However, if you are “mentally healthy”, strength training doesn’t seem to improve sleep quality.
- High-intensity strength training seems to work better than moderate-intensity.
Note: You might find it unusual that the authors included chronic pain and fatigue as ‘mental health’ issues. But as research continues to deepen our knowledge, it becomes clear that chronic pain and fatigue issues have much more to do with the brain than the rest of the body. It’s very cool that strengthening exercise can positively affect these things.
How does strengthening your muscles provide mental benefits?
The authors of the review article get into a few ideas of how strength training might plausibly cause these effects on mental health. We won’t get into the details here, just a few key points.
It’s already well known that strength training works (especially early in a program) by causing both neural adaptations (improving how your nervous system recruits and activates muscle) as well as morphological adaptations (increase in size, etc.). Some of these neural adaptations occur in the brain itself, so it’s not much of a surprise that these changes may also help out with other mental processes that may use similar brain areas or pathways. But more research is needed (as always) to tease apart more details.
This might upset animal lovers, but it’s always easier to learn more about biochemical and physiological processes by reasearching animals. A lot of research already exists regarding aerobic exercise in rodents. Aerobic exercise seems to release chemicals such as neurotransmitters and growth factors (like nor-epinephrine, 5-HT, nerve growth factor, VEGF, IGF-1, BDNF, etc.) that may be involved in many of these positive changes.
For strength training, however, it hasn’t been so easy to research. In rodents, aerobic exercise is as simple as restricting or allowing a running wheel. But it’s kinda difficult to get a mouse to lift weights. You can train them to climb with weights on their backs by giving them rewards like food, or punishments like mild tail ‘shocks’. But that could be confounding – rewards and punishments have their own effects on the brain! Scientists are figuring it out, and more research should be available soon.
In summary: strength training may have its positive effects on mental health through eliciting changes in neurophysiology and biochemistry, especially in the brain.
Strength training has been shown (by good research) to have positive effects on mental health in such conditions as:
- Chronic Pain
If you review the various benefits of strength training, it becomes clear that this is something we should all be doing. I often wonder if it’s because life is so easy now – with our tools and technology – that we’ve lost not only our bodily capacity to overcome a physical challenge, but also our will and mental resolve to do so. When was the last time you avoided the stairs because you were tired, or didn’t feel like it? Once upon a time, you couldn’t.
Have you run out of excuses yet?
O’Connor, P., Herring, M., & Caravalho, A. (2010). Mental Health Benefits of Strength Training in Adults American Journal of Lifestyle Medicine, 4 (5), 377-396 DOI: 10.1177/1559827610368771