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Ever get the feeling you're [stifled yawn] just not getting enough sleep?
What with 7-Elevens, international working practices, and the constant availability of digital frippery (as a friend recently pointed out, all those TIVO'd Lost episodes won't watch themselves...) modern life makes the holy grail of 7-8 hours shut-eye pretty difficult to achieve.
In fact, sleepwise, it's basically been a downhill slalom since some smart alec invented the electric light. (See this TED lecture for details on our better-rested ancestors).
The impact of sleep deprivation on mental faculties is well documented. Sleepy people make mistakes, crash cars, get depressed, and - what was it now? - oh yes, forget stuff.
But now it looks like being chronically sleep-poor might make us stout as well as stupid.
Epidemiologists have been noticing for a while that shorter sleep duration is associated with greater weight, even when you account for the influence of other weight-connected factors like illness, depression and lifestyle. The relationship is apparent in adults, and even stronger in children.
What's not so clear is where the relationship comes from.
One theory is that lack of sleep increases food intake, possibly by increasing the release of ghrelin (often thought of as the ‘hunger hormone'), or by weakening our self-control muscle and leaving us less able to resist high-calorie treats. (Another is that sleeping less simply leaves us with more waking hours in which to stuff our faces.)
Some research even suggests that lack of sleep could compromise our metabolic health regardless of how fat we are, or what we eat.
In one of the earliest studies to show this, investigators from the University of Chicago persuaded healthy young men to come and sleep in their clinical research center for 16 nights.
Sounds like a good deal, doesn't it?
It would have been, apart that on six of these nights they limited the subjects to just four hours of sleep. And when the researchers measured their subjects' glucose tolerance after this ‘sleep-debt' period, they found that metabolic health was significantly impaired.
The mechanism for this potential metabolic damage is not entirely clear, but it could involve the stress hormone cortisol, which is elevated in the sleep-poor and has been linked to bulging waistbands.
So what should we take from all of this?
Well it looks like a good night's sleep is even better for you than scientists previously thought. So instead of torturing yourself with the latest celebrity diet, why not try going to bed an hour earlier and cozying up with a book instead?
In fact, I think I'm going to try this daring new lifestyle regime right away.
Sweet dreams everyone!
