Your Brain: The Missing Manual

Why We Sleep

Now that you know about the sleep-regulating pacemaker implanted in your brain, you may be curious about why it exists. In other words, why is sleep so important that there's a module in your head dedicated to nagging you about it?

The Practical Side of Brain Science: Getting a Good Sleep

As you've learned, there's a highly accurate clock lodged in your brain. This timepiece could do a splendid job running your life, getting you out of bed without an alarm clock and sending you to bed before sluggishness sets in—if you weren't scrambling its time-keeping with the bad habits of modern living (and possibly artificial lights).

Fortunately, now that you understand how the SCN works, you can improve the situation. Here are some good tips:

• Use light to shape your sleep. Having trouble sleeping on time? The easiest way to adjust your biological clock is with light. So turn it on bright to wake up in the morning and dim it to slow down in the evening. And if you really need a solid night's sleep, try to make do with no artificial lights at all (or shift to weaker sources of illumination, like candles, oil lamps, or a roaring fireplace). If all else fails, relocate to a darkened cave for the night. (If you've ever had your light constrained by the sun—for example, when camping or in the midst of a power outage—you've probably noticed how uncomplicated sleep becomes.)

• Work late, but not all night. If you're planning to work late, set 4:00 a.m. as your absolute limit. At that ...