It's the Sleep, Stupid

One of the worst things we modern folk do is not sleep enough. Due to some misguided idea of getting more done by working too hard, we manage to decrease productivity, damage our health, and act like banshees around other people. So how much sleep should we be getting, and when?

1) Hours per night. As the witticism goes, "I'll sleep when I'm dead." Well, you'll likely be dead sooner if you don't get enough sleep in the meantime.  This meta-analysis study including data on 1.3 million people indicates that less than 6 hours per night is correlated with a shortened lifespan, probably due to all kinds of metabolic and inflammatory problems which result from lowered sleep times. Getting too much sleep is also linked to a shortened lifespan, but in these cases the excess sleep is probably related to other factors, such as depression or poverty. If you sleep a lot (like over 8 hours), it's likely that you have another issue to deal with, not that you should try to avoid sleeping.

2) So how about naps? We've been annoyed with the term "power nap" for several years now (of course our culture needs to add "power" to something to make it respectable), and many sources tell us to take naps to supplement our sleep. This sounds like a great idea, and cultures all over the world take siestas in mid-day to break up the work schedule, keeping us from getting burned out. This NASA study showed that napping helped with some of the sleep-related issues that astronauts face, but did not fix the problem of not getting enough sleep. Another recent study from UC Berkeley showed that people who took midday naps were better at learning later in the day.

3) When to sleep? This answer seems to be somewhat variable. Working night shift has been linked to lowered immunity, and even cancer, If you are fortunate enough to work days, you might benefit from sleeping in two nightly doses, a practice known as "biphasic sleep" (this term can apply to taking daytime naps as well)- it seems that before artificial light sources, this may have been the norm. If you wake up in the middle of the night for a while, you might consider using that time rather than just trying to get back to sleep right away. If you get most of your sleep during the day, however, taking naps at night can cause grogginess.

4) Late vs. early sleepers. The terms "night owl" and "morning lark" have been around for a while, and psychology also uses these terms to categorize people into late and early sleepers. In one Psychology Today article, staying up late was linked with higher intelligence, while in another, it was considered to be a potential disorder. This reaaaallly interesting article breaks down a bunch of personality traits and other factors linked to differing circadian (sleep) rhythms; for instance, it would seem that morning types are more conscientious. So there's lots of variability, and with all things sleep, quite a bit of mystery.

Of course, we all respond differently to sleep, which is one of the things that makes it the most interesting and unpredictable. Some Zen teacher once said, "When I am tired, I sleep," which seems to be the best advice so far.