The Health Risks of Exercising Too Much

Your body is made to move, and working out is one of the best things you can do for it. Exercising at a moderate intensity at four days a week reduces the risk of a multitude of diseases including heart disease, type 2 diabetes, hypertension obesity - and it even gives you a mental boost. But what about people who exercise three hours a day? Are their risks to too much exercise?

The Risks of Too Much Exercise

Most people have problems motivating themselves to work out even 30 minutes a day, so exercising too much isn't a big issue. But there are a small minority of people who exercise several hours at a time - almost every day. Some of these people are marathon runners while others are addicted to the endorphin release they get when they work out hard. Still others do it, because they're obsessed with their weight. The health benefits of exercise are well known, but too much exercise isn't always a good thing.

Exercising Too Much Can Decrease Your Immunity

People who exercise too much put themselves at greater risk for colds and flu viruses. Moderate amounts of exercise improves the function of the immune system, but if you overdo it, you could wind up with a nasty cold, or worse, the flu. Overtraining, especially if you don't give yourself adequate rest time between sessions, suppresses immunity. One study showed that 13% of marathon runners became ill within a week of the race. Both high-intensity and high-volume overtraining can reduce immunity.

Too Much Exercise Increases the Risk of Injury

Not only does overtraining lead to muscle soreness, it increases the risk of injury too. Muscles need time to recover from a workout. If you're exercising too long and not resting long enough between sessions, your muscles may be sore from the last workout. You may not use proper form - and end up with an injury that could take you out of commission for a while.

Overtraining Can Keep You from Making Gains

When you exercise too much, your body responds by releasing the stress hormone, cortisol. Cortisol causes breakdown of muscle tissue so the amino acids can be used as fuel. If you're trying to build lean body mass, this can work against you. Moderate and high-intensity exercise both stimulate transient release of cortisol, but if you're overtraining your levels will be chronically elevated - not a good thing for your muscles or your health.

Too much exercise also causes your body to hang on to fat, especially if you combine it with calorie restriction. Any time the body senses a fuel shortage, it adapts by slowing things down. This isn't what most people want.

Exercising Too Much Can Be a Psychological Downer

Exercising is one of the best stress relievers there is, but overtraining can cause both physical and mental fatigue, lack of motivation and sleep problems. Don't become a slave to your exercise routine or it can become more of a stressor than a stress reliever.

Other Health Risks of Exercising Too Much

Women who exercise too much, especially those who calorie-restrict, may experience bone loss and their periods may stop. They can also experience infertility and loss of sexual desire.

How Much Exercise is Too Much?

Most studies show a decrease in immunity in people who exercise more than 90 minutes a day. Some people will have problems exercising less if they're not allowing enough recovery time between sessions or doing high-intensity workouts more than three times a week. One way to find out if you're overtraining is to check your pulse rate first thing in the morning and keep a record. If your pulse rate is elevated more than 7 beats per minute several days in a row, you're probably overtraining.

A precipitous drop in weight, nausea, and excessive fatigue are other signs you're training too hard. Keep a regular exercise diary where you record your weight, pulse rate and any symptoms you have before and after exercise. This will help you identify whether you're exercising too much.

The Bottom Line?

Work out hard, but be aware of the warning signs that you're exercising too much - and give yourself a break.

References:

Medicine and Science in Sports and Exercise. 27(8): 1111-1117. August 1995.

Exercise Physiology. Seventh edition. Powers and Howley. 2009.