In reality, "She has no health problems whatsoever," says Dr. Fu. "She is completely normal, except that her sleep schedule is shifted forward."
Intuitively, most of us know if we are an early bird or a night owl. And despite the myriad of articles promising that becoming a "morning person" simply requires following a rounded-off number of tips, it's largely genetic. You're either born a morning person, or you're not. "Our bodies are wired in a certain way," says Dr. Fu. "All of our bodily functions are regulated by our circadian rhythm. Your body temperature has a rhythm, your heartbeat has a rhythm…you can wake up before your body is ready, but a lot of your body's functions aren't fully awake yet." (This lag in cognitive functioning is known as sleep inertia, that period between waking and being fully awake when you feel groggy.)
So how to determine the number of hours you need a night as well as when you should be sleeping them? A common recommendation is to simply pay attention to your body the next time you go on vacation: avoid all stimulants like caffeine; go to bed when you feel tired; turn off your alarm clock, and see when you wake up naturally. But both Dr. Fu and Dinges caution that to determine your optimal sleep schedule, you may need to catch up on sleep first. If you are extremely sleep deprived going into your vacation, "two days is not going to be enough for you to recover," says Fu. Instead, she recommends resting for two or three days before paying attention to your body's natural clock.
"Most people can learn to live on the schedule that's optimal for them," says Dinges. Most of us have the same amount of productive hours, we just are on slightly altered schedules. Dr. Fu finds that for many people, the most difficult part is not work, but coordinating their schedule with that of their partner's. This can be especially hard for people whose schedule is dramatically shifted forward or backward. "They have to marry someone with the same sleep schedule," laughs Fu. "Otherwise, when they want to go to bed at seven or eight, their spouse wants to go out and do things."
So, all you sleepers out there still looking for love; the next time you're out on a date, perhaps consider if you're sleep schedules are compatible. Or perhaps find yourself a short sleeper instead.
Black says his unusual sleep schedule never bothered his wife. He worked long days and could still help take care of the kids. "I don't think she minded waking up to a hot breakfast every morning."