Terrance Lee barely sees daylight.
During his surgery rotation, the third-year Chicago med student wakes up at 4:30 a.m., before the sun rises, and stays at the hospital until long after it goes down. But his day doesn't end there. He has to study before going to bed at 10:30 p.m. -- and wake up six hours later to do it all over again.
"It's depressing sometimes to wake up and it's still dark, and when you're leaving the hospital it's dark again," said Lee, 24. "Oftentimes you don't really get to see sunlight at all -- maybe if you peer at it through the patients' windows."
Lee is now a master at functioning on about six hours of sleep, two hours less than the recommended amount but just enough for him to stay on his game at the hospital.
Count him among the bleary-eyed masses.
Common wisdom tells us the average adult should get about eight hours of sleep a night, but in the hustle of daily life, shuteye can be the first thing to go. People entering hibernation mode this winter might feel even more like they're not getting enough sleep as those long winter nights make it harder to get up in the morning.
According to experts, sleep deprivation can affect a person's immune system, hurting the ability to fight off infections. Lack of sleep also can increase the risk of accidents because of impaired coordination or inattention.
"The shorter daylight hours (in the winter) for many people will make it harder to wake up in the morning because we're used to getting that strong cue from bright lights and sunlight in our bedroom to help ease the transition of waking up," said James Wyatt, director of the Sleep Disorders Service and Research Center at Rush University Medical Center.
Lots of Americans aren't getting a good night's sleep. As many as 70 million in the U.S. might be affected by chronic sleep loss or sleep disorders, according to the National Institutes of Health.
Though there's no easy solution for sleep deprivation, napping can help.
The so-called power nap, which lasts 15 to 20 minutes, can provide a restorative benefit of up to three hours, Wyatt said. And longer naps, such as three-hour ones on the weekend, can supplement nighttime sleep, but beware of the sleep hangover, he said. The brain has a hard time switching gears from being in a deep sleep to being awake, and a person might feel tired after the nap, he said. After such a long nap, it can take up to an hour to become fully alert, he said.
Before Lee starts studying after his hospital rotations, he takes 20-minute naps. "Most of the time, it definitely hits the spot. I wake up feeling a lot more refreshed and able to study the rest of the night," he said.
What about sleeping more? Well, people do try. About 54 percent of adults surveyed in a 2007 National Sleep Foundation report said they make up for sleep loss by getting more sleep on the weekends, and 37 percent said they take naps.
For Lee, sacrificing sleep for med school is worth it, despite moments of extreme tiredness.
"At the end of the day ... (to) be in the position where you can make a difference ... it's pretty rewarding," Lee said.