Why Exercise Feels Good
The Science Behind “The Runner’s High”

By Carol Krucoff, RYT, and Mitchell Krucoff, MD

 

 

While the link between physical activity and psychological well-being is firmly established, the mechanisms by which exercise exerts its “feel good” effects are still the subject of intense debate.  Popular theories point to exercise’s impact on brain chemicals, on body temperature, and on psychosocial factors, such as being with other people and getting away from problems.

 

One of the most widely known theories is the “endorphin hypothesis,” which attracted attention in the mid-1980s, when researchers found that aerobic exercise appears to activate the body’s natural opioid systems, stimulating release of morphine-like substances called endorphins that trigger feelings of euphoria and tension relief.  This became known as the “runner’s high.”  Since that time, however, further research has shown that other brain chemicals also may be involved in the physical-activity–feel-good effect, including serotonin and norephinephrine.

 

Another theory is the “thermogenic hypothesis,” which suggests that temperature elevation caused by exercise relaxes muscles and lowers the level of arousal.  Some researchers speculate that repetitive, rhythmic physical activity—such as swimming laps or running—may exert a tranquilizing effect on the brain stem and nervous system in a manner similar to rocking a baby.

 

Others note that exercise enhances sleep, allowing people to recharge their batteries more fully.  Since disturbed sleep is both a symptom of depression and an aggravating factor, exercise’s beneficial effect on sleep may be important to help stabilize mood and enhance cognitive functioning. 

 

Exercise may also indirectly enhance mental health by controlling weight, which affects self-esteem and reduces disease risk.

 

In addition to these physiological mechanisms, exercise also has numerous psychological components.  The “distraction theory” holds that exercise simply helps people escape temporarily from their problems.  Accomplishing a goal, mastering a new skill, interacting socially, and getting away alone are all psychologically based theories about why exercise improves mood.

Other factors may also play a role in exercise’s mood-elevating effect.  People who exercise outdoors may experience the additional lift—and shift in perspective—of being surrounded by nature.  Exposure to sunlight may be particularly helpful during winter for people prone to seasonal affective disorder (SAD), a condition characterized by depressive symptoms triggered by reduced hours of daylight. 

And people who exercise to music, which in itself can “soothe the savage breast,” may experience a heightened mood-elevating effect.
 

Some experts propose another intriguing theory, known as the “anthropological hypothesis,” to explain both the feel-good effect of exercise and the high incidence of depression in our sedentary society. 

 

“Thousands of years ago, our ancestors had to depend on physical activity to survive,” says Norwegian psychiatrist Egil Martinsen, who is considered by many to be the world’s foremost authority on exercise and depression.  “It’s only in the last twenty to forty years that we’ve been able to survive without being active.  We know inactivity isn’t good for the heart.  Perhaps it’s not good for the soul, either.”

 

 

*Adapted from Healing Moves:  How to Cure, Relieve and Prevent Common Ailments with Exercise, by Carol Krucoff, RYT, and Mitchell Krucoff, MD.