News Flash: Sleep is Important

I recently received an advanced copy of the book The Way We’re Working Isn’t Working by Tony Schwartz, which came out earlier this week. As I’ve mentioned before, I don’t accept many of these books any more because most of them don’t interest me. What sold me on the book, which was fantastic, was the first few sentences on Amazon (plus endorsements from Seth Godin and Tony Hseih don’t hurt either):

Schwartz, CEO of the Energy Project, stretches an obvious thesis to the breaking point in his plaint on how the American workplace—theoretically where technology has allowed us to reach for more, bigger, faster—has bred an atmosphere in which workers have become disengaged from their work. We fail to take care of ourselves, he points out, and end up undermining our health, happiness, and productivity.

Of course, because I’m obsessed with sleep and how little we care about doing it well, despite it’s importance, I really keyed in on the sleep chapter. It is probably the single best thing I’ve read on the perils of lack of sleep. Here are some of my favorite quotes arranged into a more readable excerpt:

The consequences [of lack of sleep] include extreme fatigue, compromised cognitive capacity, emotional instability, lower productivity, and greater susceptibility to illness. No single behavior, we’ve come to believe, more fundamentally influences our effectiveness in waking life than sleep.

Nonetheless, sleep is also one of the first behaviors many of us are willing to sacrifice, on the mistaken assumption that doing so will allow us to be more productive. “We all think we have to stay awake to get more done,” says Matthew Walker, the director of the sleep and neuroimaging lab at UC Berkeley. “I think that’s simply not true. In fact, if you have a good night’s sleep, what you’ll find is that you can get more done than if you simply stay awake.”

So how much sleep do we need? The National Sleep Foundation recommends between seven and nine hours. Precious few of us can function well on much less. As Thomas Roth of the Henry Ford Sleep Disorders and Research Center says, “The percentage of the population who need less than five hours of sleep per night, rounded to a whole number, is zero.”

Based on their own estimates, Americans average only 6.5 hours of sleep per night. Even that may be overstated. In a study led by Diane Lauderdale at the University of Chicago, 669 middle-aged adults reported that they slept an average of 7.5 hours a night. But they also wore wrist monitors that allowed the researchers to determine precisely when they actually fell asleep. The average turned out to be 6.1 hours.

People who are sleep-deprived often don’t recognize their own limitations. “It’s convenient to say, ‘I’ve learned to live without sleep,'” explains David Dinges, a sleep researcher at the University of Pennsylvania. “But you bring them into the laboratory and we don’t see this adaptation.” Charles Czeisler, another renowned sleep researcher and chronobiologist at Harvard Medical School, puts it more bluntly: “Like a drunk, a person who is sleep-deprived has no idea how functionally impaired he or she truly is. Most of us have forgotten what it really feels like to be awake.”

Two recent studies of athletes at Stanford University suggest a powerful correlation between sleep time and performance. In one study, members of the swim team maintained their usual sleep-waking pattern for two weeks and then increased to ten hours of sleep a day for six to seven weeks. Once they were sleeping longer hours, they began to report higher energy and improved mood. They also significantly improved their quickness off the starting block, as well as their turn times, sprint times, and kick-stroke rate.

In Dream On: Sleep in the 24/7 Society, Charles Leadbeater summed up the costs this way: “Lack of sleep makes us more inefficient at work and more dangerous behind the wheel of a car. It undermines the quality of our lives and makes us more vulnerable to illness. It is also responsible for making us less able to respond creatively to problems and opportunities, and less original, flexible and divergent in our thinking and thus less likely to generate new ideas.”

Several studies have shown that immune response drops significantly among people who sleep less than seven to eight hours a night. Eve Van Cauter, a University of Chicago sleep researcher, found that subjects who slept four hours a night for six consecutive nights demonstrated not only a lower immune response but also diminished ability to regulate blood sugar, a risk factor for diabetes, and unusually high levels of circulating cortisol, a risk factor for high blood pressure. Among Van Cauter’s most significant findings was that sleep deprivation dramatically lowers levels of leptin, the hormone that signals satiety, and helps us control how much we eat.

Subjects sleeping four hours a night for six nights produced 18 percent less leptin than those sleeping seven to eight hours. This finding, Van Cauter and others believe, goes a long way toward explaining the connection between obesity and sleep patterns. For example, a study of nearly 10,000 people found that subjects who slept five or fewer hours a night were 60 percent more likely to be obese than those who slept seven hours or more.

The Harvard Nurses’ Health Study, which followed nearly 80,000 nurses over twenty-five years, uncovered a strong link between chronic sleep deprivation and increased risk of a range of diseases, including breast cancer, colon cancer, and coronary heart disease. Nurses who averaged five hours of sleep a night, for example, were significantly more likely to develop heart disease than those who got six hours. They, in turn, were at greater risk than those who slept seven hours a night.

At the cognitive level, we don’t think well when we’re tired. David Dinges found that subjects who slept less than six hours a night over a two-week period demonstrated a decrease in performance that was equivalent to that experienced after forty-eight continuous hours of sleep deprivation. More striking still, Harvard’s Charles Czeisler found that averaging four hours a sleep for five consecutive nights has an impact on our memory, attention, and speed of thinking that is equivalent to being legally intoxicated.

Wow, if that last paragraph doesn’t get you to think seriously about your sleep schedule, I don’t know what will.

1 comment on News Flash: Sleep is Important

  1. […] fascination with sleep is pretty well documented. Rightfully so, I think, given how “no single behavior, we’ve come to believe, more fundamentally influences our effectiveness […]

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