Why are some people natural early birds while others walk around in a coma until noon?
"We're all governed by our circadian rhythms, daily cycles that are produced by a kind of pacemaker in our brains," Dr. Thomas A. Wehr, the Chief of Clinical Psychobiology at the National Institute of Mental Health explains. "This clock is what wakes us in the morning and puts us to sleep at night and coordinates with hormonal and other cycles.
Most of us know little about the regular daily rhythms that govern sleep patterns, alertness, peak body strength, memory, logical reasoning, sensitivity to pain. All of these change from hour to hour according to our body clocks. And just like any other physical or psychological system, body clocks are vulnerable to a variety of ills, especially under the stress of modern life.
We don't just passively respond to the rising of the sun, however. The rhythmic switching is generated inside the brain. Even if we were living in total darkness, we'd still flip back and forth every 24-27 hours. Sunrise just resets our clock so it stays in sync with the rising and setting of the sun.
Before the advent of electric light the clock in our brains would adjust so that our period of activity got shorter in winter and longer in summer. But artificial light means that we can stay up all night if we choose. Dr. Wehr bemoans the fact that we've pushed our body clocks to their most extreme summer setting, with long days and short nights for life. "Permanent summer hasn't done our bodies any good," he says. "We're addicted to long periods of wakefulness. The price we pay is in more fatigue and a down mood." Lack of sleep in the winter may even cause depression by playing a part in SAD (Seasonal Affective Disorder).
How you know if you're getting enough sleep. "Simple," says Dr. Monk, "If you're well rested you shouldn't be sleepy during the day. And you shouldn't be falling asleep in the early evening or at other times." It can a be a fatal mistake to miss out on sleep, especially if you're driving a long commute or operating dangerous machinery.
Go to the dentist. Pain tolerance is highest in the morning.
Memorize the presentation you have to make later in the day.
Short-term memory is at its peak in the morning.
Eat a hearty breakfast. And if you must eat a whole box of cookies, do it before noon. The calories you take in during the morning do much less damage than those ingested in the evening.
Figure out how to balance the budget. Noon is the time of peak mental alertness. Working memory is sharpest at this time, so around noon is the best time for solving logical puzzles, doing mental arithmetic, working on any problems that take a lot of thought.
Don't eat a heavy lunch. The post-lunch dip is worsened by a high carbohydrate meal.
Take a nap. It's in our biological makeup to doze in the afternoon. Afternoon is siesta time in many parts of the world, where they view our on-the-go all day schedule as abnormal. Traditional hours in Europe are 8 am to noon with a 3-hour break for the heavy meal of the day followed by a nap; then a return to work from 4 to 7 pm, with a light meal after work. This schedule makes a lot more sense to our natural body rhythms.
Don't schedule an afternoon slide presentation in a warm room. You might hear more snores than appreciative murmurs.
Do mindless tasks. Efficiency at simple repetitive tasks such as proof-checking or filing peaks in the late afternoon or early evening. Being a little less alert may help you tolerate the boredom.
Go to the gym after work. Since body temperature is the highest between 5 to 7 pm that's best time for strenuous exercise. The muscles are more responsive because they're warmer, while adrenalin and noradrenalin–the hormones that stimulate the heart– are still high. But don't exercise within three hours of bedtime because you may not be able to fall asleep.
Memorize that sales pitch. Long-term memory peaks in the late afternoon and early evening.
Sleep for at least 7 hours. This may be a radical idea considering how most of us live, but if you manage to get a good night's sleep, every night, you'll be happier and healthier no matter how much you exercise or diet.