Exercise and sleep go hand-in-hand: the more you exercise, the better you'll sleep [1], and the more well-rested you feel, the better you'll perform during your workouts [2]. But if you're in the habit of working out late at night [3], you could be doing more harm than good.

"If [your workout] is really close to bedtime, the rise in body temperature and wakefulness-promoting neurotransmitters can be problematic, particularly if you tend to be a night owl," W. Christopher Winter [4], MD, author of The Sleep Solution: Why Your Sleep Is Broke and How to Fix It, told POPSUGAR. It's the same reason you might find it difficult to sleep in a warm room. Your body temperature naturally decreases to initiate sleep [5]; anything that keeps it raised can disrupt your night.

Of course, the effects of your workout also largely depend on the type of exercise you're doing. Some workouts may actually help you fall asleep faster [6]. "Exercises with stretching, breathing, and relaxation (like yoga and tai chi) are better than more intense aerobic or anaerobic activities (like running or rowing)," Dr. Winter said.

If you prefer to exercise in the evenings — or that's simply the only time you have — stick with these lighter workouts or plan to wrap up your sweat session a few hours before you climb into bed. This will allow your heart rate and body temperature to come back down, so you can fall asleep fast.