Yet many cultures reward people who start work early, even if they’re operating on reduced sleep. As a result, many successful people are short-sleeping early-risers such as Margaret Thatcher and Bill Clinton. Fortunately for those of us who like to hit the snooze button, success is not restricted to early birds. Albert Einstein and Elvis Presley, for example, were late sleepers.
3. Exercise helps you sleep.
Exercising may contribute to falling asleep earlier, and it certainly helps us sleep soundly through the night. But it’s light, not physical activity, that proves the German proverb “Fresh air makes you tired.” Exercise often means being outside and getting more light — on average, 1,000 times more than indoor levels. Exposure to sunlight synchronizes our body clocks with daylight.
Sleep is not only regulated by the body clock, but also by how long we were awake (also known as the buildup of “sleep pressure”). But not all waking hours are equal. We’ll get more tired skiing, for example, than sitting at a desk sending e-mail. This is one reason we sometimes lie awake at the end of a long day at the office despite utter exhaustion.
4. Sleep is just a matter of discipline.
Most parents and teachers think that if teenagers are zombies in the morning, they just lack the discipline to go to bed early. Although it is true that exposure to computer and television screens late at night makes for late rising, early-to-bed teenagers will still have a hard time getting up at the crack of dawn.
Think of teenagers as early shift-workers who suffer the most social jet lag. They go to school at their biological equivalent of midnight with profound consequences for learning and memory. They suffer from sleep deprivation during the school week and certainly should be allowed to catch up on weekends. However, they should sleep with daylight coming into their bedrooms and should refrain from using light-emitting devices after 10 p.m.
5. Most couples have very different sleep habits.
We’ve all heard stories: A woman tries to sleep while her husband is reading. Or one spouse needs to sleep in, but the other wants to start the day. When I ask lecture audiences whether such scenarios sound familiar, I frequently see a majority of hands go up.
But again, this is a matter of biology and genetics, not habits and personal preference. Women generally fall asleep earlier than men, who tend toward night owlishness. Women, however, tend to control the sleep times in a partnership. Husbands of women who work late shifts at night, for example, go to bed much earlier when their wives are at home than when their wives are working late, research has found.
One finding that might be surprising, given how much time we spend in our beds: Men and women don’t seem to give any consideration to sleep patterns when choosing a mate.