Sex Sleep Eat Drink Dream (14 page)

"Everyone knows about the need for naps in transportation," says Fred Turek, a sleep researcher at Northwestern University and a speaker at the Amelia Island event. "But there's still very little being done about it." In his lecture, Turek showed two slides: one with the figure of $1 billion, the cost of a B-2 Spirit, the world's most expensive bomber; the other with $8.88, the cost of a Wal-Mart lawn chair used by B-2 pilots for power naps. Money well spent, says Turek, but not used often enough in this way.

Even for those of us with lives less strenuous than those of long-haul pilots and truckers, a well-timed catnap can improve alertness and mood. One study showed that for sleepy subjects taking monotonous early-afternoon drives in a car simulator for an hour or two, a midafternoon nap of less than fifteen minutes improved reaction time and reduced driving impairment as much as drinking two cups of coffee. Japanese researchers who recently conducted a two-week work-site study of factory laborers got similar results: a short nap on a reclining chair after lunch markedly enhanced job performance.

Naps can even augment perception. Sara Mednick and her colleagues at Harvard University tested subjects by presenting them with a visual perception task four times a day. The performance of those deprived of a nap deteriorated across the four test sessions. But those able to get a little shuteye between the second and third session—not just a rest, lying quietly with eyes closed, but a real nap, complete with slow-wave and
REM
sleep—showed substantial improvement in perceptual acuity.

In a later study, Mednick showed that naps also facilitate learning. Both nappers and non-nappers spent an hour in the morning learning to identify the orientation of three bars flashed on a computer screen. All of the subjects were then tested on what they had learned, first at 9
A.M
. and again at 7
P.M
. The napping group, which slept for an hour or more before repeating the test, outperformed the non-nappers in accuracy by 50 percent—but again, only if they slept deeply enough to have both
REM
and slow-wave sleep.

In early 2007 came news that a regular post-lunch nap may reduce the risk of coronary death. A study of more than twenty-three thousand Greek men and women, ages twenty to eighty-six, revealed that those who napped had a 34 percent lower risk of dying from heart disease.

In short, say sleep researchers, naps make you sharper, healthier, safer. Some businesses in Japan, Europe, and the United States are beginning to heed the research and are building naps into work schedules to boost safety and productivity.

So what is the best time to take a nap, and how long should it be? The latest siesta studies suggest that just fifteen to twenty minutes' rest sometime between 1
P.M
. and 2:30
P.M
. can relieve fatigue, boost cognitive performance, and recharge your mental batteries. Longer naps of, say, forty-five minutes to an hour may require some recovery time—about twenty minutes or so—while the grogginess of sleep inertia wears off. "Naps of this length, however, are sensitive to time of day," says Mednick. Morning naps will have more light sleep; late-afternoon naps, more "cleansing" deep sleep.

Taking a short sleep at midday is a natural response to our biological need for rest. The human body is "programmed" for a siesta, says Mary Carskadon. There should be no shame in taking one.

7. STRUNG OUT

I
NSTEAD OF GRABBING A NAP
, perhaps you choose the chemical route to mental clarity, slipping out of the office and around the corner for a jumbo latte. Even before imbibing the black stuff, however, you've begun to feel less sleepy. Maybe it's the fresh air. Or maybe it's nerves.

The tension has been building over the course of the day, one hassle after another. Now, on the way back from the coffee shop, you're fretting about the work piling up on your desk, that snide comment made by your supervisor, your looming deadline, and the impossibility of making it home in time for your daughter's soccer game. As you step into the intersection, a horn blares, and you look up just in time to see a Ford Bronco barreling through the red light. You scuttle back to the curb, spilling your coffee, breathless, then angry, as you realize you've escaped getting creamed by inches. Your heart beats thick, your knees tremble. At this time of day, the tide of Cortisol and other stress hormones in your body should be ebbing, on the way to their nighttime nadir. But suddenly they're surging into your bloodstream. If you weren't alert before, you are now, strung out and scared stiff.

William James once wrote that "the progress from brute to man is characterized by nothing so much as by the decrease in frequency of proper occasions for fear ... In civilized life, in particular, it has at last become possible for large numbers of people to pass from the cradle to the grave without ever having had a pang of genuine fear." It may be true that we're a lot less likely than our forebears to face the horror of ending up as some other animal's lunch. But that threat has been replaced with other dangers, real and imagined. I think of diving under my desk in third grade during the A-bomb drills of the Cold War, of being in a car driven by a drunk teenage friend, of looking out the window of a prop plane and seeing one engine afire, of waking in the middle of the night to the sound of an intruder breaking my apartment window.

I think of an incident on a brilliant fall day, in retrospect more comic than scary, though it didn't feel so at the time. Late that afternoon, I was walking home from a friend's house with my young daughter Nell, both of us worn out from a long weekend of athletic activity. As we headed up the hill toward our house, we realized that something was setting the area's dogs to frenzied barking. Our neighborhood is an eclectic enclave of urban and rural houses at the edge of the city, where sidewalks are only a sporadic adornment to newer homes, where people have two, sometimes three dogs and still borrow a tractor to plow up the yard for corn and potatoes.

Out of the corner of my eye, I caught sight of a black mass obscuring the steps of the Victorian house across the street. Not ten yards from us was an enormous bull planted on the crabgrass of my neighbor's lawn, wide-eyed and stamping the ground with one hoof, agitated no doubt by the canine cacophony. He must have weighed a ton.

Goose bumps rose on my arms and neck. Nell looked at me: "Mom?" We both froze for an instant. The bull let out a bellow. I jumped, grabbed Nell's hand, and ran for our gate. I knew the bull was not bloodthirsty. I knew it was just a lost
Bos taurus
that had wandered into the neighborhood from the stockyards down the road. But still I had the panicky feeling of prey. My legs prickled, my knees shook. My hands trembled so I couldn't open the gate. Nell's nimble little fingers flicked it open, and we ran for the house.

From the safety of the front window, we watched the bull vanish around the back of my neighbor's house just as three police cars pulled up. A pratfall of heavyset policemen piled out of their vehicles and headed for the backyard. They disappeared for an instant. Then, suddenly, all five came scurrying back, eyes bulging, mouths agape, breathing heavily. "Buddy," one called to another, "I ain't never seen you move like that!"

For the next five hours the bull terrorized the neighborhood, thundering through flower beds and vegetable gardens, mowing down fences, even stumbling up the stairs of a front porch, before the police finally cornered him on the grassy swale between two houses, and a man from the stockyards shot him with a tranquilizer dart.

Runaway bull, reckless SUV, overbearing boss: the body's reaction is the same, a rapid-fire but sophisticated fight-or-flight response that affects nearly every aspect of our being.

It all begins with subconscious fear. "We're built to deal with danger first, and then to think about it," explains Joseph LeDoux, director of the Center for the Neuroscience of Fear and Anxiety in New York. In a series of brilliant studies, LeDoux has teased out the circuits in the brain that control fear and found what he views as two separate pathways to fright, which he calls the "low road" and the "high road."

The low road, says LeDoux, is the reason we're still here.

Fear originates deep in the brain, in that almond-shaped structure called the amygdala. When we see a possibly dangerous object or hear a threatening sound—say, the shadow of a predator or the hissing whoosh of a speeding car—a quick-and-dirty preconscious version of the stimulus, a small, rough-hewn, and fragmentary part of the sound or image, flashes along the low road. This ancient and primitive visual pathway doesn't travel by way of the "thinking" cortex but goes straight to the amygdala, without any conscious awareness and well before the complete image or sound is fully reconstructed in the mind. The amygdala sends an instant "look out!" signal that sets the body in motion to respond quickly to potential danger.

Meanwhile, says LeDoux, a more complete version of the stimulus also works its way along the high road, to the sensory cortex, where it's considered carefully, processed in detail, and analyzed to create a precise picture of the situation. The high road may confirm the danger. Or it may deem the fear inappropriate and the risk unreal—say, a large, dark tree stump rather than a hulking bull—and turn off the fear response.

But by this time, the amygdala has already triggered the body's defenses: the startle, the freeze, the hair standing on end, the mobilization for fight or flight. "It takes only twelve milliseconds to turn on the fear response in the amygdala," says LeDoux. "It takes three times that long, thirty to forty milliseconds, for the [same] stimuli to reach the sensory cortex." Those extra milliseconds can mean the difference between life and death; hence the evolutionary value of the low road.

Think back to that near miss with the Ford Bronco. The "look out!" message signaled by the amygdala was only the first step in your salvation. The warning message was picked up by the hypothalamus, at the base of your brain, which in turn sounded a chemical alert to your pituitary and adrenal glands, two small, bean-like glands situated atop your kidneys. These responded by releasing a flood of stress hormones that produced the familiar adrenaline rush, quickening your heart rate, stepping up your blood pressure, and supplying extra blood, oxygen, and fuel to your muscles, especially the large muscles of your legs. In the meantime, the bronchial tubes in your lungs dilated to bring in extra oxygen, which reached your brain to keep it vigilant and alert. The energy and fat stores in your body released some glucose and fatty acids to deliver more fuel. Those hormonal signals whistling through your body triggered the constriction of blood vessels supplying your skin and the release of the clotting factor fibrinogen to help stanch the loss of blood from any potential injury. The stress hormone Cortisol set off changes in the immune system, readying it for damage to skin, muscle, and bone, and for possible infection. Your brain was meanwhile pumping out endorphins, which act as analgesics to reduce pain, if necessary. The quick surges of adrenaline and Cortisol also served to boost mental acuity. At the same time, your body was slowing those functions it would not need in an emergency: digestion, reproduction, growth.

"The idea of this activity is to shift all resources to the parts of the body needed most to face an immediate challenge," explains Bruce McEwen, a neuroendocrinologist at Rockefeller University. This makes sense, of course: When we see a lion or an SUV coming our way, as McEwen points out, we're better off using our energy to scamper away rather than to digest an egg or grow a toenail.

In the past decade, scientists working to fathom the full nature of the fight-flight reaction, also known as the stress response, have turned up surprising news. "This kind of acute stress response is good for the body," says McEwen. "It's a protective reaction; it sharpens our senses, improves our memory, even enhances our immune response." In fact, stress itself is good, argues McEwen, as long as it's short-lived. Though a short bout of stress guzzles energy, it does wonders for performance and can actually deliver a sense of physical and mental well-being. The stress response is a brilliant system for facing short-term challenges, whether lifting a car off a trapped child, weathering a hurricane, giving a lecture, or outrunning a bull.

The emphasis, however, is on short.

What makes us feel stressed out is chronic, repeated, or excessive exposure to stress, the coping with noise, traffic, time pressures, and day-to-day worries about work and family, debt, aging parents, marital problems. "This kind of mounting psychological pressure, which causes us to lose sleep, stop exercising, and eat the wrong things, puts excessive wear and tear on our bodies," says McEwen. "This is the real danger." It's not unlike the difference between acute pain, which serves as an essential alarm system, and chronic pain, which has little purpose and does much harm. Chronic stress can put the body's response system into overdrive, overwhelm or derail it, so that it turns against itself, causing serious illness, even death.

Scientists have known for years that unremitting stress takes a toll on the body but have just begun to grasp how such long-term psychological pressure gets under the skin.

As the day at the office progresses and the wrinkles build—cranky boss, disorderly papers, family business shoved to the side—you find yourself jiggling your knee nervously and hunching your shoulders, perhaps ruing your decision not to buy a cookie with your coffee and wondering about reaching for that emergency chocolate bar in your desk. Your head begins to throb. You bend over to pick up a pile of memos from the office floor and feel a stab of lower back pain.

The word "stress" has been so overused that it has lost much of its meaning. It derives from the Latin
stringere,
meaning to draw tight. A Hungarian scientist, Hans Selye, was the first to coin the term, in the summer of 1936 in a short report to the journal
Nature,
entitled "A syndrome produced by diverse nocuous agents." Fourteen stressful years later, Selye published a thousand-page opus on the subject, which he generously dedicated to those in the world who suffer strain from "sustained wounds, loss of blood or exposure to extremes of temperature, hunger, fatigue, want of air, infections, poisons or deadly rays ... who are under the exhausting nervous strain of pursuing their ideal—whatever it may be, to the martyrs who sacrifice themselves for others, as well as to those hounded by selfish ambition, fear, jealousy, and worst of all by hate." Which describes pretty much all of us at one time or another, including the author himself. Selye, who was known to work an average of ten to fourteen hours a day, seven days a week, also dedicated his work to his wife, who, he said, understood "that I cannot, and should not, be cured of my stress but merely taught to enjoy it."