Yes, you should have stayed in bed!

"Sleep" by Salvador DaliJust about everyone would like to lose a kilo or two; ditch the spare tyre, lose the love-handles unload a bit of junk from the trunk – it’s one of those things that seems to unite all of mankind. So it’s no surprise that a gargantuan industry has sprung up to satisfy that demand. Switch on the telly or open a website and chances are you’ll see an advertisement for some sort of health and fitness product and chances are it’ll have a weight-loss slant.

The trouble is, as with any economic market, the invisible hand at play here doesn’t recognise goods and services that can’t have a price attached to them. In fact free solutions tend to actively shunned – why drink water at the gym when you can guzzle fabulous high-fructose corn syrup solution.

Perhaps the most glaring example of this freebie shunning effect is sleep. It’s one of life’s great free pleasures. But a good night’s sleep is an increasingly rare commodity – and that’s not doing our health any favours.

Everyone who’s stayed out all night will know about the negative effects of acute sleep deprivation; everything from irritability and confusion to headaches, sensitivity to cold and aching muscles. Typically this sort of thing is self-correcting; if you didn’t sleep well last night, you surely will tonight.

But medico’s are only recently starting to properly understand the effects of chronic sleep deprivation – something phrases like “Rushing woman’s syndrome”, “sleep camel”, and “junk sleep” have recently entered our language to describe.

In 2004 a joint project between Stanford and the University of Wisconsin studied about 1,000 volunteers invesigating the number of hours they slept each night. Doctors then measured their levels of ghrelin and leptin levels – two hormones that among other things, tell us when we’re full – and charted their weight.

The result: Those who slept less than eight hours a night not only had unbalanced levels of leptin and ghrelin, but they also had a higher level of body fat. What’s more, that level of body fat seemed to correlate with their sleep patterns. Specifically, those who slept the fewest hours per night weighed the most.

The irony is, with people’s lives becoming more crowded, weight-loss directed exercise is being squeezed in wherever it’ll fit –and all too often that’s where sleep used to be. A moonlight jog or a pre-dawn yoga class is seen as a badge honour among go-getting executives. But given what we now know about sleep deprivation, if you’re getting up at 5am after going to bed at midnight to squeeze in a quick bit of exercise – there’s a strong case to say you’d have been better off staying in bed.