“If you are in a bad mood, go for a walk. If you are still in a bad mood, go for another walk.” – Hippocrates
Strong bones; healthy heart; increased lung capacity; decreased stroke risk; lower blood pressure; improved cholesterol and blood sugar; reduced fall risk (better balance, stronger muscles): the general health benefits of physical activity are widely appreciated.
The evidence is also strong that moving our bodies has a multitude of beneficial effects on our brain and mental health. Regular physical activity can improve memory, concentration, sleep, energy, mood, anxiety, creativity and overall well-being.
When we exercise, elevated heart rate increases the blood flow (and oxygen) to the brain, improving brain functioning and resilience. The beneficial effects of regular exercise on mood may in part be mediated through an increase in synthesis and release of neurotransmitters such as serotonin, dopamine and norepinephrine. Dopamine, for example, helps modulate the brain’s reward systems, including feelings of motivation, hope, pleasure and joy.
Especially important for optimal brain health, exercise boosts the expression of multiple different neurotrophic factors. These brain-protecting proteins support the survival, growth and maturation of brain cells and neuronal pathways. Regular exercise can actually increase brain volume (and prevent shrinkage) as we age, including in the hippocampus, which is essential for memory and learning. Exercise is one of the strongest modifiable risk factors for dementia. People who are physically active show less of a decline in their mental acuity and are at lower risk of developing dementia.
Exercise may contribute to a longer life span. Regular moderate physical activity has been shown to be associated with longer telomeres, which are the “caps” at the ends of our chromosomes. Telomeres shorten as we age, and longer telomeres are associated with longevity.
Exercise-induced release of endorphins (naturally occurring opioids produced within our brains) and endocannabinoids (chemicals produced in our bodies that are similar to those in the cannabis plant) generate feelings of well-being, optimism, euphoria, reduction in pain, and decrease in anxiety. Think “runners high.”
Physical activity can decrease reactivity to stress, in part by affecting our hypothalamic-pituitary-adrenal (HPA) axis, our “stress axis.” Stress triggers a cascade of hormone signals, which results in the release of cortisol from the adrenal glands. Chronic exercise seems to modulate this system, resulting in reduced cortisol levels, both at rest and when stressed.
Exercise can also reduce anxiety through other mechanisms. When we are threatened, our fight-or-flight systems respond with stress hormones that trigger physiologic responses such as increased heart rate, sweating, and shortness of breath. In people who are more prone to anxiety, these physical sensations can lead to emotions of fear and alarm, which can sometimes lead to a full-blown panic attack. People who exercise are accustomed to sweating and feeling their heart pounding, sensations that are experienced as normal and healthy responses to physical activity. This reduces their sensitivity to the physical manifestations of anxiety and decreases vulnerability to the anxiety “spiral.”
Physical activity can also work by distracting us from anxious thoughts, such as during team sports, an exercise class, a walk-and-talk with a friend, immersion in nature during a hike, or dancing to music etc. Getting out for even a short morning walk can help us start the day in a more positive mental space.
Exercise may even prevent the development of anxiety disorders in the first place. A recent (September 2021) article in the Frontiers of Psychiatry studied almost 400,000 long-distance cross country skiers over many years and found that the skiers were significantly less likely to develop anxiety than a matched group of non-skiers. The researchers conclude: “Our results support the recommendations of engaging in physical activity to decrease the risk of anxiety in both men and women.”
Exercise is also a natural antidepressant. Many studies support the beneficial mood effects of regular exercise, including aerobic exercise as well as strength training and yoga. These include protecting against the onset of depression, treating current depression, and decreasing risk of relapse after recovery. It can be a stand-alone treatment in less severe depression, or can boost the effects of medications and other treatments.
Social connectedness is a key component of mental health. Moving together, in synchrony, with another person seems to have a very powerful social bonding effect, leading to improved self-esteem, feelings of trust, and a sense of community (think dancing, running with a friend, paddling side-by-side). Interestingly, exercising alongside another person also seems to trigger the release of even more endorphins, increasing pain tolerance and allowing one to go further in their work-out then doing the same routine alone.
Exercise also boosts mood through an increase in self-esteem and self-efficacy. People tend to feel a sense of accomplishment as they get stronger, learn a new yoga pose, gain endurance, etc. This improved self-confidence then often generalizes to other parts of our lives and self-concept.
Certain kinds of rhythmic breathing can reduce feelings of stress and anxiety, specifically regular, deep breaths (“diaphragmatic breathing”), with a longer exhale than inhale. This type of breathing stimulates the vagus nerve, part of the parasympathetic nervous system, leading to a calming effect. The practice of yoga involves synchronizing breathing to movement in a way that promotes mental relaxation. During rhythmic activities such as swimming, walking, and running, our breathing often harmonizes with our body movements to bring about a meditative state. Interestingly, during these states, our brains may be active in a different way, such as generating new ideas (as opposed to worrying). Studies show that exercise can actually boost creativity. One may enter the pool with problem they are trying to solve, and while not consciously thinking about it during the swim, a solution becomes clear soon after the last lap. The next time you are feeling stuck or stale, try taking a walk.
While, for the most part, the mental health benefits of exercise outweigh the risks, there are some caveats. In eating disorders such as Anorexia Nervosa, excessive exercising can be a part of the illness and lead to medical complications. In competitive and elite athletes, high pressure to perform and perfectionism can lead to overtraining, stress, overuse injuries and a decline in mental health. If an exercise regimen takes on a compulsive quality or leads to negative effects on health, work, or relationships, it’s time to reassess. In general, regular, moderate exercise is recommended.
We don’t fully understand yet all of the complex mechanisms underlying the anti-anxiety and anti-depressant effects of staying physically active, or know which types of exercise, in what doses, work best for a particular person. But it is clear that engaging in regular physical activity, doing something you enjoy, is one of the best things you can do to boost your overall physical, mental, and brain health. (Be sure to consult with your doctor before starting a new exercise routine if you have medical or joint conditions which might be impacted).