It’s no secret that regular exercise promotes health throughout the body. Research shows routine physical activity can improve cardiovascular health, strengthen bones and muscles, and even reduce the risk of certain cancers. But did you know breaking a sweat can also strengthen the brain?
A growing body of research suggests physical fitness is one way to boost brain health — and that a regular exercise routine can decrease the effects of stress on the body, improve mental health and mood, and even enhance memory and cognition.
Exercise fuels the brain's stress buffers
Exposure to long-term stress can be toxic to multiple systems in the body, even leading to medical concerns like high blood pressure and a weakened immune system, along with mental illnesses like anxiety and depression.
It may seem counterintuitive that exercise, a form of physical stress, can help the body manage general stress levels. But the right kind of stress can actually make the body more resilient. Research shows that while exercise initially spikes the stress response in the body, people experience lower levels of stress hormones like cortisol and epinephrine after bouts of physical activity.
So far, there's little evidence for the popular theory that exercise causes a rush of endorphins. Rather, one line of research points to the less familiar neuromodulator norepinephrine, which may help the brain deal with stress more efficiently. Research in animals since the late 1980s has found that exercise increases brain concentrations of norepinephrine in brain regions involved in the body's stress response.
Norepinephrine is particularly interesting to researchers because 50% of the brain's supply is produced in the locus coeruleus, a brain area that connects most of the brain regions involved in emotional and stress responses. The chemical is thought to play a major role in modulating the action of other, more prevalent neurotransmitters that play a direct role in the stress response.
Biologically, exercise seems to give the body a chance to practice dealing with stress. It forces the body's physiological systems — all of which are involved in the stress response — to communicate much more closely than usual: The cardiovascular system communicates with the renal system, which communicates with the muscular system. And all of these are controlled by the central and sympathetic nervous systems, which also must communicate with each other. This workout of the body's communication system may be the true value of exercise; the more sedentary we get, the less efficient our bodies are in responding to stress.
Exercise can boost mental health
Along with mitigating the negative effects of chronic stress on the mind and body, habitual exercise can improve mental health. Many experts believe routine exercise is as powerful in treating anxiety and mood disorders as antidepressants.
Preliminary evidence suggests that physically active people have lower rates of anxiety and depression than sedentary people. But little work has focused on why that is. To determine how exercise might bring about its mental health benefits, some researchers are looking at possible links between exercise and brain chemicals associated with stress, anxiety and depression. One theory is that physical activity triggers a release of dopamine and serotonin, which can improve mood.
But there are other reasons exercise plays a crucial role in mental well-being.
For example, exercise can be particularly helpful for people who deal with anxiety and panic attacks. When you engage in strenuous physical activity, you're essentially mimicking the responses that can come with anxiety, allowing you to learn how to manage these responses and not be overwhelmed by them in other situations.
Psychologists also recommend exercise to their patients because it leads to a sense of accomplishment. Getting dressed and driving to the gym first thing in the morning may not be so fun in the moment, but prioritizing self-care practices like exercise can result in a cascade effect of other healthy habits, like eating nutritiously, socializing with others and getting a good night's sleep — all of which can improve depression symptoms.
For even more impact on your mental health, combine your exercise routine with other evidence-based practices, like mindfulness meditation — or, reap the benefits of some good, old-fashioned fresh air and sunshine by taking a walk outdoors.
Exercise can build the mind's muscles
Have you ever noticed that while your body might feel a bit fatigued, you feel more alert and energized after a bout of exercise? It's been proven that physical activity can improve brain functions like memory and cognition both immediately after a workout and in the long-term.
In research with rodents (rats and mice), there's evidence that exercise increases the blood supply to their brains and promotes the growth of new neurons (adult neurogenesis) in the hippocampus, a brain area that is essential for learning and memory. In one study, one group of rats got free access to a running wheel and another ran on a treadmill for an hour a day. After 30 days, both groups had a better blood supply to their brains. A group of sedentary rats showed no increase. An increased blood supply means increased oxygen and energy supply, and that equals better performance. The improvement in performance can also be attributed, at least in part, to an exercise-induced increase in adult hippocampal neurogenesis.
Although these types of studies are only now beginning in humans, the theory is that because sports combine learning and exercise, they may both increase blood supply and enhance brain connections.
Recent studies suggest physical activity benefits white and gray matter in the brain, which leads to enhancement of cognitive processes like thinking and memory, attention span, and perception.
Movement can also improve cognitive regulation, or the ability to ignore distractions and multi-task. While there's not as extensive of research on middle-aged adults, researchers think the same benefits hold true across the board.
Exercise can sharpen memory
There's also scientific evidence that people who exercise experience improvements in episodic memory, which is our ability to bind how events, people and places come together in everyday life. Exercise can also benefit the brain's spatial navigation, or the ability to remember everyday life events, like where you parked your car.
Exercise can also help people maintain their cognitive abilities as they age. Many studies have found that physically active elderly people perform better than sedentary elderly people on cognitive tasks such as reasoning, vocabulary, memory and reaction time. It's known that regular exercise can prevent memory-related diseases like Alzheimer's. Exercise can increase the brain's ability to create new neurons in rodents, which can enable the brain to learn new information and improve memory. Whether adult hippocampal neurogenesis can be increased by exercise in humans remains to be determined, but there is a robust and growing body of research among school-aged children.
For people who have already been diagnosed with memory-related diseases, exercise is a commonly recommended intervention. Studies show that one year of activity interventions can increase the volume of the hippocampus — the part of the brain that deals with learning and memory — by one percent.
How much exercise do I need?
If your doctor gives you the go-ahead, there's no reason not to reap the physical and mental benefits of a regular exercise routine. But how much exercise is the right amount?
Official exercise recommendations have increased over the years. The Department of Health and Human Services Physical Activity Guidelines for Americans (PDF, 15MB) recommends 150 minutes or 2.5 hours of moderate aerobic activity a week, or 75 minutes of more vigorous activity.
If getting started with an exercise routine sounds overwhelming, keep in mind that starting anywhere is better than not starting at all. Not sure where to begin? Think outside of the box, and try not to worry too much. Research shows that all kinds of exercise can be an effective way to manage stress and stay mentally healthy. The important thing is that you find an activity you enjoy and stick with it.
For more information on exercise recommendations, including suggestions for age-specific activities, refer to the 2018 Physical Activity Guidelines for Americans Move Your Way Campaign.
For their contributions to this article, APA thanks:
Rod K. Dishman, PhD, of the University of Georgia
Mark Sothmann, PhD, of Indiana University's School of Medicine and School of Allied Health Sciences
Henriette van Praag, PhD, of Florida Atlantic University's Charles E. Schmidt College of Medicine
Nancy Molitor, PhD, of Northwestern University's Feinberg School of Medicine
Elaine Ducharme, PhD
Anthony C. Hackney, PhD, DSc, of the University of North Carolina at Chapel Hill
Charles Hillman, PhD, of Northeastern University's Bouve College of Health Sciences