A friend of mine recently asked me if he should sacrifice sleep in order to get his workouts in. My answer is: 1) NO, and 2) if you're sacrificing sleep in order to work out, you're not doing it right.
Not getting enough sleep is detrimental to your health on several levels. Let's take one of the most obvious: driving. Did you know that driving while drowsy produces the same effects as driving under the influence of alcohol? If you're against drunk driving, you should be just as against drowsy driving. The National Highway Traffic Safety Administration estimates (conservatively) that drowsy drivers are the cause of more than 1,550 deaths and 71,000 injuries each year on U.S. roads. That's pretty significant.
Concerned about your waistline? Not getting enough sleep will affect your body fat content. Have you ever been really sleepy during the day, so you reach for coffee/candy/chips/food to keep yourself awake? And, of course, you're too tired to exercise, so you head home. No energy to cook, of course, so you order in pizza or Chinese food. Then you're too wired to sleep, so you don't get enough sleep again... and the cycle continues. This is, believe it or not, related to a hormonal imbalance created by the lack of sleep. When you don't get enough sleep, your body produces an excess of a hormone called ghrelin, which is the hormone that tells you to eat. At the same time, your sleep-deprived body decreases your production of the hormone leptin, which tells your body to stop eating. So it's a no-brainer what havoc this can wreak on your body.
Sleep is the time that your body repairs itself, too. So if you work out and don't sleep, you won't see the kinds of results you might like to see-- your body won't be repairing your muscles. If you want to get bigger, faster, leaner, stronger, and so on, the quality and amount of sleep you get is just as important as the quality of your workouts. Oh, and you know that whole "do not operate heavy machinery" comment you see printed on certain pharmaceuticals? Same goes for heavy weights. Your reaction time is off-- significantly off-- when you're drowsy, and your strength isn't what it should be, either. I personally had an experience of trying to press a 16K kettlebell overhead when I was really tired-- I almost knocked myself out with the thing. I won't be making that mistake again.
Sleep keeps you mentally sharp, as well as physically sharp. When you don't sleep enough, your ability to retain and react to information decreases significantly. In addition, you become irritable and not so fun to hang out with. Not getting enough sleep can start to lead to hallucinations and other mental confusions, and just four days of sleep deprivation can lead to serious mental illness. You become clumsy, react slowly to stimuli, and can even develop tremors. If you want to stay sharp (and keep your friends), get your sleep.
Long-term inadequate sleep depletes your immune system, leading to major problems such as cancer, heart disease, stroke, ADD, growth retardation (in children), disruption of your partner's sleep patterns (leading to a much less happy partnership), hypertension, and much more.
The average adult needs 7 to 8 hours of sleep per night. There is some variation from person to person. If you want to know how much sleep you need, one test you can try is to take a week or so to go to bed at exactly the same time every night and don't set an alarm in the morning. Eventually, your body should regulate and wake you up about 7 or 8 hours later (or whatever your body needs).
Make sure your room is dark and quiet at night, and try to keep distractions out of the bedroom (television, computers, pets, kids... the latter two can be more difficult, but do what you can). Try to keep the bed as a place for sleeping only (well, and "bed-type activities."), and try not to eat right before bed. If you're tossing and turning for more than 15 minutes, get out of bed and try to calm your mind (watch something inane on TV, read a book, listen to someone boring, whatever works for you). Then go back to bed when you're ready to fall asleep again.
If you have trouble sleeping, or if your quality of sleep at night is poor, I highly recommend getting a sleep study done to find out what the problem is and how you can resolve it.
If you have any questions, thoughts, or suggestions on getting a good night's sleep, feel free to post them here!
Oh, I should comment on why I said "if you need to sacrifice sleep for your workouts, you're not doing it right." Unless you're a professional athlete, you really don't need to be training for hours. Your workouts, if done right, should be short and intense as hell. I'll be doing another post about this another time.