The best way to recover from that particularly tough workout? A day or two of rest followed by a light bout of exercise, recommends Stenstrup. Also make a point to get at least eight hours of sleep a night which your body will need to repair those tiny muscle tears that occur during workouts and enable your body to build new muscle. Good nutrition is also key: Think lean protein (fish, skinless chicken breast, tofu), whole grains and plenty of fruits and vegetables. Here are the 10 ways your body will let you know if you're headed for exercise burnout.
1. Decreased performance. A drop in your workout performance is one of the earliest signs of overload, according to Jini Cicero, a conditioning specialist based in Los Angeles, Calif. Altered performance levels are often more apparent in endurance activities such as running, swimming and cycling, she says.
2. Disinterest in exercise. A significant decrease in motivation or enjoyment of the activity can be a major sign of burnout, Cicero says. This more often occurs in weight lifters, sprinters or soccer players who are driven by speed and power.
3. Mood changes. Depression, anger, confusion, anxiety and irritability are common when your body is overstressed physically. Those same stress hormones you release when you're emotionally stressed are also released when you're physically overloaded, Cicero explains.
4. Delayed recovery time. Persistent muscle soreness that lasts for hours or days after your workout is a sure sign you need more rest, according to Joseph Ciccone, a physical therapist at ColumbiaDoctors Eastside Sports Therapy in New York City.
5. Elevated resting heart rate. "When you put more stress on the heart, it has to work a lot harder," Ciccone says. An increase in your normal resting heart rate, say, from 50 beats per minute to 65 beats per minute, could indicate that you're placing excessive stress on your body.
6. Fatigue. Mental or physical grogginess is a hallmark sign of overtraining, says nutritional biochemist Shawn M. Talbott and author of Natural Solutions for Pain-Free Living, based on his research on over-stress patterns in professional athletes. "The knee-jerk reaction to sluggishness is to exercise for an energy boost, but it's a catch-22," he says. "Another workout might wake you up short-term, but you'll be worse off later on."
7. Insomnia. Being in a state of overload often comes with disrupted sleep patterns, so instead of getting that much-needed rest, Talbott says, "you become restless and can't fall asleep."
8. Diminished appetite. "A decrease in appetite can occur in the middle to later stages of overtraining, and goes hand in hand with feelings of fatigue and lack of motivation," says Stenstrup. By slowing down bodily processes like metabolism, the body attempts to force a reduction in its workload.
9. Fat gain. If you've lost weight but noticed an increase in body fat, you could be in the later stages of exercise overload. The body responds to prolonged stress by elevating levels of stress hormones, including cortisol, Stenstrup says. Over time this will lead to increased storage of adipose tissue, as well as inhibit steroid-like hormones that normally help increase muscle. A decrease in muscle mass can cause you to shed a few pounds, but this isn't a good thing since it means your body's less efficient at burning fat.
10. Weakened immune system. Don't try to push through that exercise funk, Talbott warns, "or you'll keep sliding down—to a weakened immune system, inflammation, and outright injury." Not a good thing. Prolonged overtraining can take weeks, even months, to recover from, and can put your health at risk. Chronic inflammation, for example, has been linked to diabetes, heart disease and cancer. Bottom line: Nurture your body and give it a much-deserved break when it needs to rest after that tough workout.
Chelsea Bush writes for AskFitnessCoach, a blog that promotes fitness and weight loss for "real" people.