"Sleep is not a luxury," says Dr. James O'Brien, medical director of the Boston SleepCare Center in Waltham, Mass. "It's a necessity for optimal functioning."
When you sleep, your brain catalogues the previous day's experiences, primes your memory, and triggers the release of hormones regulating energy, mood, and mental acuity. To complete its work, the brain needs 7 to 8 hours of sleep. When it gets less, your concentration, creativity, mood regulation, and productivity all take a hit.
How sleep works
To understand why the right amount of shut-eye is so important to performance, it helps to know how sleep works.
Healthy sleep is divided into four-stage cycles. As we progress through stages 1 and 2, we become increasingly unplugged from the world until we reach the deep sleep that happens in stage 3. In deep sleep, both brain and body activity drop to their lowest point during the cycle, and blood is redirected from the brain to muscles.
The fourth and final stage is named for the rapid eye movement -- REM -- that is its defining characteristic. Our brains become busily active in REM sleep, too, even more so than when we are awake. Dreaming happens during this stage.
In a full night's sleep, we experience three or four such cycles, each lasting 60 to 90 minutes.
The work sleep does
Different yet equally important restorative work happens during deep sleep (stage 3) and REM sleep (stage 4).
Deep sleep is crucial for physical renewal, hormonal regulation, and growth. Without deep sleep, you're more likely to get sick, feel depressed, and gain an unhealthy amount of weight. According to the National Sleep Foundation's 2008 Sleep in America poll, those who sleep less than 6 hours per night on workdays are significantly more likely to be obese than those who sleep 8 hours or more (41% vs. 28%).
In REM sleep -- stage 4 in the sleep cycle -- the brain processes and synthesizes memories and emotions, activity that is crucial for learning and higher-level thought. A lack of REM sleep results in slower cognitive and social processing, problems with memory, and difficulty concentrating. The same 2008 sleep poll found that people who sleep less than 6 hours per night during the workweek are twice as likely as their better-rested colleagues to report difficulty in concentrating.
A deficit in sleep leads to deficits in work performance
Performing complex tasks and navigating complicated relationships -- the heart and soul of a manager's work -- both become much harder to do when REM sleep suffers. And when you cut back on sleep, your REM sleep suffers the most.
There are two reasons for this:
- Your brain, when confronted with sleep deprivation, opts for lighter sleep and hence less REM sleep.
- Later sleep cycles tend to have longer REM periods than cycles earlier in the night. When you sleep through only one or two cycles instead of three or four, your REM sleep is disproportionately affected.
When your brain is starved of REM sleep, concentrating on a single activity is challenging. Multitasking -- an inescapable bane of managerial work -- becomes exponentially more so.
A deficit of REM sleep also makes it tougher to pick up on nuances in discussions or negotiations.
"When you're trying to understand the subtext of what someone is saying, your brain needs to use a bunch of programs at the same time," says Dr. Gandis Mazeika, head of Sleep Medicine Northwest in Seattle. "If you're sleep deprived, that's hard to do."
In addition, recent research shows that sleep deprivation takes a toll on decision-making ability.
Getting more from the sleep you get
Given the demands facing managers today -- working in a 24/7, always-on environment is a big one -- a full night's sleep is sometimes an impossible dream. Fortunately, there are ways to get more out of the time you do manage to spend in sleep:
- Avoid caffeine. Cut out caffeinated coffee, tea, and soda ideally 10 hours before bedtime -- and chocolate, too. When you sleep, make it a commitment.
- Try to nod off quickly. To fall asleep fast, you can occasionally use a sleeping supplement. But be careful. For example, the much-prescribed Ambien is specifically for sleeping seven to eight hours. If you don't have that much time, don't use it. Although some antidepressants can help you feel drowsy enough to fall asleep, they also tend to compromise REM, says Dr. O'Brien. A more healthful approach for some is to meditate a half-hour before hitting the bed.
- Darken the room completely. Your brain creates a hormone called melatonin that senses when it's dark out and primes you for sleep. If you try to sleep amid too much light, your brain may decide you're not ready for bedtime after all. So turn off the TV, shut down the computer, turn the clock to the wall, and close the blinds tightly. Use an eye mask if you're sleeping during the daytime.
- Sleep in a restful environment. Make sure the room is quiet and your BlackBerry is out of hearing range. Sleep on a comfortable mattress; Dr. Mazeika advises you get a new one every five to 10 years.
Exploit the power of power naps
Don't forget that brief day-time naps can be helpful. If at all possible, close your office door (if you have one) and try to doze for 10 to 20 minutes.
"Power naps are real and help you feel refreshed," says Dr. O'Brien.
But keep the naps short, he warns. With a longer nap, you're likely to wake up while in deep sleep and feel worse than before. It can take up to 30 minutes to feel fully alert after awakening from deep sleep.
By keeping your nap to 10-20 minutes, you should be able to achieve stage 2 in the sleep cycle and wake up energized rather than groggy. A short power nap should provide enough of a boost to keep your performance going strong the rest of the day -- and is more effective (as well as healthier) than a cup of coffee.