How Much Exercise is Too Much?

If you take it to an extreme, it can become harmful.

As good as exercise is for you—and it’s very good for most people—too much of good thing can have negative consequences. Exercise puts physical stress on all your body parts and can ultimately lead to permanent damage to muscles, joints, and bones if you work too hard, too soon, or if you don’t follow recommended safety precautions.

Some people appear to become addicted to exercise in the same obsessive way a food addict becomes addicted to eating certain foods or a gambler becomes addicted to poker or horse races. There’s a psychological addiction that many researchers believe has a neurological basis, not unlike a cocaine or alcohol addiction. The terms “exercise addiction” and “exercise dependence” have been used by researchers to describe someone who over-exercises to the degree that it has negative effects on both their mental and physical health. About 3 percent of those who exercise are thought to have an exercise addiction.

One key component of an addiction is when someone continues a certain behavior in spite of their knowledge and/or experience with negative consequences from that behavior. So, if a drug addict destroys their family life, can’t pay the rent, or ends up in a hospital or jail because of drug use, and continues using and abusing drugs, that behavior could point to an addiction. At this time, no criteria has been established for diagnosing an exercise addiction and it is unclear what constitutes “excess” for any individual, since there can be many factors involved. Excessive exercise in and of itself can’t be considered a disorder unless the excessive behavior results in some type of mental or physical harm to the individual. That doesn’t mean there is no such thing as an exercise addiction; it simply means that more research and collaboration is necessary to officially define the term and establish criteria that would allow for a diagnosis.

However, over-exercising can be one sign of an eating disorder. The two types of eating disorders that can involve over-exercising are anorexia nervosa and bulimia nervosa. People with anorexia are underweight, extremely afraid of being fat, usually eat very little, and spend much of their time trying to purge any and all calories they consume by vomiting, using laxatives, and exercising excessively. Those with bulimia are usually normal weight or overweight, often eat excessive amounts of food, and purge or resort to extreme exercising to burn off the extra calories they eat. Since both of these disorders have severe nutritional and medical consequences, if you or anyone you know shows signs of an eating disorder, it is important to consult a medical professional, who can steer you toward the appropriate type of help. 
Even if you don’t think you overexercise, have an established, sensible workout regime—about an hour a day, up to seven days a week for the average person—and you’re comfortable with the exercises you’re doing, you may still need to slow down or call it quits for awhile in order to prevent harm. It’s important to recognize signs of trouble. Whenever you’re doing aerobic exercise, you should be able to carry on a conversation at the same time. If you’re gasping for breath, feeling faint or dizzy, feeling any pain, or getting nauseous, it’s time to slow down or take a break. Any time you’re sick, injured, or tired from lack of sleep is a good time to take a day or two off.

-Susan McQuillan, MS, RDN