Don't overtrain.

Are your muscles consistently sore?
Do you tire quickly and take longer to recover?
Have you reached a significant plateau?
Is your appetite different, perhaps with some gastrointestinal side effects?
Are you losing a significant amount of weight rather quickly?
Have you been getting sick, possibly even hurt quite frequently?
Are your sleeping patterns out of whack?
Did your resting heart rate increase?
Have you lost the desire and motivation to exercise?
Do you feel irritated, angry or depressed on a regular basis?

If you are currently participating in a fitness program and can answer "yes" to a few of these questions, you might be overtraining. While it's perfectly acceptable to train five to seven days a week, it's all relative. Volume (sets and reps) and intensity (frequency, length and/or weight) should be set according to your goals and individual body. If you can find a perfect combination of the two, you'll avoid some of the symptoms above. And yes, they can represent a whole slew of other issues—but if you're in the middle of a serious training schedule and one or more of them make an appearance in your life, it might be a good indicator that it's time to reevaluate your plan of attack. One can never be too cautious, right? Consider the following:

1) Rest and recover. It may be as simple as taking an extra day off in between sessions. But if you're really zapped, take a week off. When your body is sore and you feel completely fatigued, your time in the gym isn't worth crap anyway!

2) Talk to a fitness professional (hand in air) about what it is that you're doing. Tell them your goals and describe how you're feeling. They can look at your routine and tell you where it falls short, or what you might be doing wrong, and they can help you tweak it accordingly.

3) Variety is the spice of life...and your fitness routine! Make sure you aren't doing the same thing at the same time and at the same intensity every single same day of the week. Major bore, right? Try cross training or varying the intensity. Or just try something new.

4) Address your diet. Make sure calories in supports the calories you're burning. And make sure those calories are of the best quality. For example, acceptable carbohydrates are not found in beer and that lime loses its nutrients the minute you squeeze it down a bottleneck.

Bottom line—exercise is supposed to make you feel good, not consistently drained. Training hard is a step forward, but training too hard is two giant leaps backward.