Margaret Thatcher implied that sleep was a luxury for wimps and the idle. Her approach is now echoed by our current Prime Minister. Recently it was reported that Gordon Brown's workload allows him only two or three hours' sleep a night. Sleep needs differ, but research shows that six to eight hours is the most useful amount. Those who are too busy to sleep may make do with three or four hours a night, but this is no recipe for a long life, or for maintaining the quality of decisions.

To survive and lead, those too busy to sleep should become daily power nappers. No longer is a 20-minute kip after lunch a sign of weakness, but evidence of a Type A personality intent on recovering his or her snap, crackle and pop. Longer than 20 minutes and the nap becomes another profound sleep, undermines the next night and disturbs the circadian rhythm.

But if catnaps are good, why the reported increased death rates after long afternoon siestas? The key is in the length of shuteye. The effect of a circadian rhythm on the body's metabolic and cardiovascular system makes strokes and heart attacks common from a deep sleep, rather than a nap.

So do by all means have a doze, but keep it short.