Diet, naps and exercise are three areas important to a good night's rest, says Dr. Nerina Ramlakhan. Eight hours isn't a magic number; relax and let your body determine the right amount. "'The biggest myths are that we need seven or eight hours a day, or that we shouldn't wake up in the night,' continues Ramlakhan. 'But waking early in the morning is perfectly normal. Students can still function well in an exam if they don't sleep the previous night. I sometimes professionally advise football players and I tell them not to worry about sleep before a big game. Even if they don't manage to sleep perfectly they will still perform well.' So what's the key to an effective slumber? Ramlakhan explains the dos and don'ts of catching Z's."