9 adverse health effects of too much exercise

By Naveed Saleh, MD, MS, for MDLinx
Published March 19, 2020

Key Takeaways

The American Heart Association (AHA) recommends that adults engage in either ≥ 150 minutes per week of moderate-intensity aerobic exercise, 75 minutes per week of vigorous aerobic exercise, or a combination of the two, with activity spread throughout the week, for optimal overall health and well-being. Maintaining a physically active lifestyle has been shown to offer a number of health benefits, including increased productivity, improved sleep, reduced stress, greater heart health, and enhanced immune system support. On the flip side, too much exercise can have serious detrimental effects on your health. 

If you find yourself exceeding 300 minutes of exercise a week, you could be pushing yourself to physical “burnout,” and may be jeopardizing your health. Let’s take a closer look at physical “burnout,” or overtraining syndrome (OTS), and some of its associated health consequences.

Physical ‘burnout’

Exercise volume starts as a dose-response relationship, with increased exposure leading to more health benefits. However, a tipping point exists, beyond which too much exercise is more detrimental than beneficial. This tipping point can be reached with either too much exercise without proper recovery or chronic underfueling.

“This tipping point is known as [OTS] and, in short, leads to a decrement in fitness level and possibly injury,” advises the American Council on Exercise (ACE). “Whether you are male or female, you are equally at risk for OTS, so recognizing the early signs and combating them can prevent detrimental fitness and health outcomes.”

OTS is a maladaptive response to training, and represents an imbalance between training and recovery. As mentioned, it’s akin to physical “burnout.” Those who have a stressful occupation—such as a physician—and engage in intensive training are at high risk for OTS. 

Importantly, people who overtrain often feel guilty or anxious if they are not exercising. Thus, these individuals may continue to exercise even if they are sick or injured, which can be absolutely detrimental to health. Some people with OTS may even skip work or social events to exercise.

Adverse health effects linked to OTS

Hormonal dysfunction. Overtraining exerts a negative effect on the stress hormones cortisol and epinephrine. This hormonal imbalance can lead to emotional lability, trouble with concentration, bouts of irritability, depression, and difficulty with sleep..

Anorexia. Hormone imbalance also impacts hunger and satiety processes in the body. Although increased exercise should boost hunger, excess exercise can do the opposite. Consequently, weight loss can become a serious issue in those who overtrain.

Rhabdomyolysis. Some degree of rhabdomyolysis may be expected with certain types of very intense exercise. But, with OTS, high levels of rhabdomyolysis can lead to renal failure.

Impaired metabolism. Low-energy availability over a long period of time can negatively affect various organ systems and lead to iron deficiency anemia, low testosterone levels in men, and low bone density.

Poor immunity. Overtraining can wear down the immune system, making it harder to stave off infections like upper respiratory infections.

Increased cardiovascular stress. With overtraining, even simple workouts become more effortful. Specifically, baseline heart rate rises in those who experience OTS, and it can be difficult for heart rate to return to normal after exercising, with longer periods of rest needed.

Decreased performance. One of the cardinal signs of overtraining is decreased athletic performance, regardless of increased training intensity or volume. This performance decrease can be related to impaired agility, slower reaction times, reduced running speeds, and decreased strength/endurance. To boot, overtraining can lead to loss of motivation.

Fatigue. Excessive fatigue accretes in your system when you don’t have time to properly recover from continual exercise and refuel. Moreover, if you’re exercising too much and constantly expending calories, “low energy availability” can result, which is due to the body depleting its own energy stores. 

Chronic injury. Muscle and joint overutilization eventually lead to full-time aches and pains. If these injuries persist for more than 2 weeks, as can happen with OTS, the injury may be substantial and warrant medical attention.

No diagnostic test exists for OTS per se, and suspicion is based on history and symptoms. If you suspect OTS, take a break for a week or two and see if you still have signs and symptoms. Treatment options for compulsive overtraining and associated eating disorders include cognitive-behavioral therapy, antidepressant drugs, and support groups.

Finally, to prevent OTS, follow a periodized training program that specifically dedicates time to recovery and rest. 

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