Monday, 19 February 2007

Sleep: health, memory, productivity






Sleep can actually be good for your heart health, and therefore your longevity or life expectancy - and sleep also helps you learn and perform better. Recent New Scientist articles reported that naps can reduce the risk of death from heart disease and sleep deprivation can severly affect your ability to learn.

It's already known from previous research that sleep, including short daytime snoozes, boosts ability learning and memory (while conversely sleep deprivation makes you forgetful and absent-minded), and that "power naps" improve work productivity.

Siestas and heart health

The recent study following nearly 24,000 people for on average 6 years found that those who regularly took midday naps were nearly 40% less likely to die from heart disease than non-nappers. Researchers suggested siestas might protect the heart by reducing stress hormones levels. They found "people who took at least three naps per week lasting 30 minutes or longer had a 37% reduced risk of death from heart disease than their non-napping counterparts. Those subjects who occasionally took short naps lasting less than half an hour had a 12% lower risk than people who never napped... The results suggest that taking naps might be just as important to protecting the heart as other measures, he says, including eating right and taking cholesterol-lowering drugs... The apparent protective effect of these siestas was more pronounced among working individuals than retirees. The researchers suggest that the naps might boost heart health by keeping levels of stress hormone in check... They add that this potential stress-busting effect might be most pronounced in people burdened by heavy workloads."

Sleep and learning, memory

Studies in rats showed sleep deprivation can increase stress hormone levels in the brain, which then disrupts nerve activity in the hippocampus. Possibly a similar mechanism causes memory deficits in sleep-deprived humans.

A full night’s rest after studying can improve learning, it is already known, but the new study suggests that sleeping well before studying new information is also important. People who failed to get a good night’s sleep before studying new information were found to remember about 10% less than their well-rested counterparts.

Why are sleep-deprived people worse at remembering how to do newly learned tasks than they are normally? "We know that sleep deprivation is stressful, and that it impairs certain types of learning and memory. Also, "It points to the importance of sleep in the right hormonal conditions... These are altered if you sleep at the wrong time of day, or if you are stressed generally," he says. The results explain how shift work might damage memory by producing "a different hormonal milieu". Although I should point out that there is a view that sleep deprivation damages memory only in extreme cases.

On the work performance front, it had previously been found that when volunteers slept 60 minutes midway through a series of gruelling tests, their performance dramatically improved compared to their wakeful counterparts. It is well-known that a good night's sleep consolidates what you've learned during the day, and the research shows that even a short nap can help.

Siestas for me and you!

The Spanish certainly know what they're doing. I wonder if anyone has done research into the incidence of heart disease in people from cultures that believe in daytime naps, compared with other cultures? The results would certainly be instructive.

I'm very glad to hear about these studies. Sounds like one of the best tips for improving your health and productivity is to have lots of sleep, including daytime naps of at least 30 minutes (ideally an hour), at least 3 times a week if you can get it. And sleep well before studying or working, and have a good night's sleep after learning something new too.

My mother always took a half hour nap during her lunch break every day (she could because she was self-employed), plus a longer nap after lunch at weekends - and she looks and is fabulous for her age. Maybe the daytime snoozing is a factor, even though she worked very hard. I've taken to napping during the day at weekends too, when I can, and always felt the better for it, especially when I'm very busy generally (it's interesting to see that the benefits of snoozing are more pronounced in people with heavier workloads). Now, I feel justified - sleep is clearly a medical necessity if I want to increase my chances of a longer life!

Maybe I ought to invest in Metro Naps (who lease sleep pods to office workers, businesses, spas, gyms and universities, stores etc in New York, Vancouver, the UK, Germany, and now Australia, you can even buy a nap pass for a 25 min snooze and "The MetroNaps pod will wake you with a gentle combination of light and vibration" - this is real!). Or try a start up in competition with them.

Right, I'm off for an afternoon snooze, now...

2 comments:

kirk said...

I'm down with the "power-naps" as well, although I don't seem anymore productive. I just like the extra zzz's.

Improbulus said...

Extra zzz's are always good!