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Learning to Live
Like an Early Bird
March 4, 2008; Page D1

I'm a night owl. Always have been. As a kid, I used to stay up way past bedtime reading by the light of the electric-blanket dial. In college, I regularly pulled all-nighters and slept through morning classes, three alarm clocks notwithstanding. Now, like many working mothers, I cherish those late-night hours when nobody needs me immediately. I'm wide awake after midnight and the time is my own.

But morning comes abruptly for us night owls with day jobs. I gamely set the alarm for 6:30 a.m., then hit the snooze button repeatedly. If I could, I'd sleep till the crack of noon.

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Are you a strong night owl? A morning lark? Do you fall somewhere in the middle? Take this quiz to measure your "chronotype."
Have you ever had to shift your natural sleep preferences? Cast your vote and share your stories.

Night owls are more creative, more flexible and more caffeinated, studies have found. Morning people are healthier, more conscientious and more emotionally stable. They're not as much fun at parties, but morning people run the world, and at least part of me aspires to be a morning person. So, in time for daylight-saving time this weekend, and with the help of several experts, I've been working to reset my circadian clock. My goal: to bound out of bed early, full of energy and good cheer.

Millions of people have made such a switch, of course. Most teenagers go through a night-owl phase, due partly to hormones. As adults, they're often forced by jobs, commutes and parenthood to adjust to the early-bird world. For the vast majority of people, it's not so difficult. Their "chronotype" -- that is, the preference for being active during the morning or evening -- falls somewhere in the middle.

But some people (estimates range from 5% up to 30% of the population) have a harder time syncing their clocks with the rest of the world's. In extreme cases, night owls who stay up late, and need to sleep even later, are said to have "Delayed-Sleep Phase Disorder." Extreme morning larks, who wake up before dawn and struggle to stay up past about 8 p.m., have "Advanced-Sleep Phase Disorder." Sufferers either find careers that can accommodate them, or struggle to conform and often live sleep-deprived. I've been doing that for years, and mainlining coffee.

Setting Internal Clocks

Understanding of the body's sleep/wake cycle has exploded in the past 40 years. Chronotype is partly genetic and partly due to environmental cues. In humans, the average circadian clock actually runs for 24 hours and 10 minutes, says Charles Czeisler, director of sleep medicine for Harvard Medical School. But in studies for the National Aeronautics and Space Administration, which is investigating how humans might adapt to life on Mars, Dr. Czeisler and his colleagues found that individual circadian cycles can vary by as much as an hour or so. Morning people's clocks run as fast as 23.5 hours a day, while night owls' clocks run slower. (I'd be very happy on Mars, where each day takes 24.6 hours.)

People reset themselves slightly every day -- otherwise, we'd all be like broken watches, getting further out of sync every day. But how much humans can advance or delay their circadian clocks and for how long is still unknown. "We're in the early stages of finding out how much is due to genes and how much is due to light exposure and how much we can really change," says Christopher Drake, a senior scientist with the Henry Ford Sleep Disorders and Research Center in Detroit, who gave me suggestions for setting my clock to a more reasonable phase.

Whole industries exist to help shift-workers adjust to working odd schedules. Sleep clinics abound that can help people with circadian rhythm disorders get back in sync. One method called "chronotherapy" has people move their sleeping and waking times three hours forward every day -- going to bed at 2 a.m., then 5 a.m., then 8 a.m. and so on until they reach a reasonable evening bedtime -- and try to settle there. A quick version has them stay up for an entire night and all the following day and then readjust. I'm using a more gradual method that involves adjusting light in the morning and evening.

Light is a key player in the body's circadian clock, which is centered in a tiny cluster of neurons behind the optic nerve called the suprachiasmatic nucleus. The SCN receives light signals from the retina, and in turn, sends signals to the pineal gland, which regulates melatonin, the hormone that makes us sleepy. Darkness triggers the release of melatonin, while light suppresses it.

Natural light is the most powerful, but artificial light in the evening also delays melatonin and slows down the circadian clock. "If you have klieg lights on in the bathroom while you're washing your face at night, those lights are suppressing the release of this hormone and making it more difficult to get to sleep -- not only on that night, but on successive nights," says Dr. Czeisler.

Dim Evenings

So a key part of my sleep-shifting involves keeping the lights as dim as possible in the evening hours. "It's OK to watch TV, but in general, you want it to be as dark as possible," says Dr. Drake. "If you're reading, try using a little book light." Conversely, in the morning, "turn on as many bright lights as possible," he adds.

I also need to improve my "sleep hygiene" -- that is, give up caffeine after 6 p.m., cut out alcohol, which can disrupt sleep, and ban electronic distractions from the bedroom. "Have a cool, dark, quiet place to sleep, free of cellphones, BlackBerries, text messaging, instant messaging, iPods, TV, the Internet -- the whole nine yards. Every one of those devices reduces sleep time, studies have shown," says Dr. Czeisler.

And, let's face it, I need to go to bed earlier. Upon hearing my schedule -- turning in about 2 a.m. and attempting to rise at 6:30 -- Dr. Drake immediately sizes me up as sleep-deprived. "The human body needs approximately seven to eight hours of sleep a night to maintain optimal alert levels during the day." The idea that many people need just four or five hours of sleep a night is a myth, he says. "Many of these famous people, like Thomas Edison, took naps, or were very sleepy during the day. And imagine how much more brilliant and productive they would have been if they'd gotten more sleep."

Indeed, sleep deprivation has been shown to impair memory, weaken the immune system, slow metabolism and spur insulin resistance, a precursor to diabetes.

The need for sleep is so basic that a second system -- called the homeostatic sleep drive -- monitors how much the body has had and sends out a powerful drowsiness signal if it needs more. Normally the sleep drive works in balance with the circadian clock, but jet lag, shift work and sleep disorders can throw the two out of kilter. (See the Harvard Sleep Center's interactive video of the two systems together.) The sleep drive can be quite insistent -- making people nod off behind the wheel or at midday meetings -- particularly if they are sleep-deprived. Caffeine can override the sleep drive temporarily by blocking the receptors that register drowsiness. But it doesn't erase the need for sleep, says Dr. Czeisler. "It's like taking an aspirin to lower your fever. You're not addressing the source of the problem."

The first few nights, I get with the program easily, much to my family's dismay. The lights are dim, and I'm fast asleep by 11 -- hastened, I'm sure, by the absence of caffeine. And when the alarm rings at 6:30, I'm up and eagerly turning on lights. The second night I try to go to bed even earlier. Can it really be this easy?

No. The third night I slip up and have two cups of coffee after a late dinner, completely forgetting my goal. I toss and turn and read until 3, then sleep till noon, since it's Saturday. Circumstances conspire to keep me up late the next night and soon I'm right back in my old delayed-sleep groove. Clearly, this is as much of a lifestyle choice as a biological imperative.

I'm not alone. A study in the journal Chronobiology International of 61 patients with delayed-sleep disorder who were treated with light therapy for six weeks found that 90% had relapsed a year later. Some 28% of them had relapsed within one week.

But I keep trying. By the third week, I'm regularly falling asleep before midnight. But I still feel like I'm Krazy-Glued to the bed in the morning. I've bought a portable light box that can be set with a timer to "simulate dawn" and enhance the morning light. And it does wake me up earlier, though I tend to fall back to sleep again fast.

Too Little Sleep

"Chronic sleep deficit," explains Dr. Czeisler, who says that if you've only been getting four or five hours of sleep a night, you build up the same level of dysfunction in one week as someone who's been awake for 24 hours.

What if you've been sleep-deprived for decades -- can you ever catch up? "That's a very interesting question," he says. "You can accelerate the process by spending a little more time in bed every day. Or spend the entire weekend in bed. You'll be way ahead by Monday morning in terms of reducing the deficit."

Sounds like a great plan.

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