Exercise is good--and even more exercise is better. But those who overexercise consistently over a long period of time may develop a condition called overtraining syndrome, the body's way of saying "I've had enough--stop exercising now!"People who get enough rest and recovery time face a lesser risk for overtraining syndrome. If you continue to push your (exercise) limits without adequate rest, however, you body won't have time to recover, affecting your performance and mental health. For instance, you'll get sick all the time. Random aches and pains plague you; injuries increase. Worse is its mental toll--causing depression, irritability, and extreme changes in mood.So how do you avoid overtraining syndrome if you're an athlete, runner, or perhaps someone who really loves exercise?Keep Your Exercise ModerateOvertraining occurs when you're exercising too much. One of the easiest ways to prevent overtraining syndrome, logically, is to exercise less. That's easier said than done if you really like to exercise.One of the biggest questions people ask is "How do I know how much is too much?" Ideally, you shouldn't spend more than two hours exercising--even an hour is pushing it. This only refers to moderate exercise as well; if you're doing vigorous exercise, such as high intensity interval training (HIIT), 20 to 30 minutes is the upper limit of how much you should exercise.Also, keep tabs on how frequently you work out. If you exercise 6 to 7 days a week, that may be too much. Remember, your body needs rest to recover, even if you're not doing strenuous activity. Most experts recommend two days of rest per week to recuperate.Get Your RestAnother important cause of overtraining syndrome is the absence of rest--the time when you relax to allow your muscles to recover. Remember that muscles can only heal and recover in rest, not during exercise.Rest doesn't simply cover just abstaining from exercise, however. It also refers to your sleep schedule--how many hours a night you sleep. Sleep is one way the body (and the mind) recovers from a long, stressful day, and if you don't get enough sleep, your whole body suffers. You probably know how this feels like, feeling sluggish, tired, and irritable when you don't get enough sleep. It's not just a mood changer, however, it's a body changer, and not for the better.To avoid overtraining syndrome, get enough rest. Make sure to take at least two days off from exercise every week. Get your sleep. These aren't suggestions; these are requirements. No, you are not "weak" or "lazy" if you take time to rest--you're smart. Those who say otherwise just don't realize how serious overtraining syndrome can be.