THESE days, everyone seems to be trying to cram more and more into their day.
One of the consequences of this is that something has to give - and it's usually sleep.
Experts believe that sticking to a regular bedtime could be as important to our health as eating less saturated fat or giving up smoking.
So how much sleep do we really need and what happens if we go short?
Seven or eight hours sleep a night is reckoned to be what we need to function at our peak, though many people get by on a lot less.
Constantly fighting our natural sleep tendencies can lead to accidents, irritability, poor concentration and reduced IQ.
Headaches are also more common among the sleep-deprived, and some researchers believe that more serious problems like heart disease, diabetes and lowered immunity can result in the long term.
Regular sleeping times can be just as important as getting enough hours. Shift workers' systems can take a particular battering as they try to alter their natural body clock to work out of sync with nature.
Jim Horne, professor of psychophysiology at Loughborough University, says: "Being able to cope by snatching four or five hours' sleep here and there is seen as an achievement to be proud of, but it's not a weakness to admit that you really need sleep and to take it."
If you still need convincing that sufficient regular sleep is worth taking, here's our guide to what happens to your physical and emotional health when you get anything from less than two to more than 10 hours a day:
ONE night: Just one night with little or no sleep noticeably impairs your ability to comprehend rapidly-changing situations, says Professor Horne.
This could be potentially catastrophic for people with jobs in hospitals or air traffic control, where workers have to respond to emergencies very quickly.
Going without sleep for 36 hours also affects your conversational ability - you can't string a sentence together as easily and you'll find yourself repeating cliches, forgetting words and speaking in a monotone.
SEVERAL nights: Most people can only make it past a couple of nights with barely any sleep before zonking out.
If you go without sleep for more than about three nights you start having "dream intrusions" (a bit like hallucinations) while you're awake.
ONE night: Studies by Dr Eve Van Cauter, a research professor of medicine at Chicago University, have shown that levels of the stress hormone cortisol rise in the evening following a night of only four hours' sleep.
This may be due to the psychological stress of not sleeping rather than the sleep deprivation itself but, either way, too much cortisol can impair memory and the ability to fight off cold and flu bugs.
Interestingly, cutting back to four hours sleep can actually benefit people who are severely depressed, as it can help lessen the disturbances in REM (rapid eye movement) sleep associated with some depressive disorders. "The short-term boost to mood can be considerable," says Professor Horne.
SEVERAL nights: According to Dr Van Cauter, getting four hours' sleep for six nights in a row has adverse effects on the body's ability to maintain a proper hormone balance. This may ultimately lead to a higher risk of diabetes and heart disease.
ONE night: Even losing one or two hours' sleep from the standard seven or eight can cause daytime drowsiness.
Unfortunately, drivers often underestimate this effect and take fewer precautions than they would do if they had slept for only one or two hours.
According to Professor Horne, the only way to counter driver sleepiness is to take a break and have a 10-minute nap, then have a shot, preferably two, of caffeine, from coffee or a caffeinated energy drink.
SEVERAL nights: Surviving on minimal sleep is not recommended, but, says Professor Horne, lots of people can get by on six hours' sleep for several nights without any detrimental effects to their health. …