You use an alarm clock to wake you in the morning and you look at your watch throughout the day to know the time. But there’s another kind of clock you may not be consciously aware of – although you are constantly connected to it. It’s your body’s internal clock.
“Your internal, or circadian, clock is an intrinsic body rhythm that tends to run on a cycle a little bit longer than 24 hours,” David Schulman, MD, Associate professor of medicine at Emory University School of Medicine and Director of the Emory Sleep Laboratory, tells Synergy. Sleep and your internal clockYour individual circadian rhythm makes you more alert at certain times of the day and also determines when you usually feel sleepy. “It’s often difficult to fall asleep much before your usual bedtime because your circadian rhythm is naturally trying to keep you awake. So if you usually go to bed around 11 p.m. and are well rested and not very sleep deprived, it will be hard to go to sleep at 9 p.m.,” Dr. Schulman explains.
Ever wish you could nap in the afternoon? You can probably blame it on your internal clock. In fact, you might try to avoid scheduling important meetings in the early afternoon if you normally feel slowed down that time of day.
While a big lunch can make you sleepy, Dr. Schulman says that even in the absence of a meal people tend to be sleepier in the hours directly after lunchtime. There’s a normal circadian nadir (low point) around 2 p.m. or so which explains why some societies have a tradition of taking a nap after lunch –notably the famous Spanish “siesta”.
“Although it’s usually not practical in today’s work environment, if you can work in a 30 minute nap after lunch you might be pleasantly surprised how energized and effective you are in the afternoon,” Dr. Schulman tells Synergy.
Jet lag and your internal clock
If you’ve ever experienced the numbing fatigue of jet lag, you understand what throwing your internal clock out of kilter can do. “Jet lag can be likened in many ways to motion sickness,” Dr. Schulman points out. “Motion sickness happens when your eyes are telling you one thing but your inner ear is telling you something different. With jet lag, your internal clock is telling you one thing but your external environment is telling you something else.”
This disconnection between when your body will let you fall asleep and when you want to fall asleep in the place you are visiting can make you feel tired and out-of-sorts until your internal clock resets itself, usually in a few days.
Dr. Schulman explains that when you fly toward the east across time zones, you are shifting away from your internal clock’s setting and “losing” hours, which can make jet lag more difficult than flying west. “However, on flights from east to west over several time zones you gain a few hours,” he says. “The difference in time is usually easier to adjust to because you are shifting toward your internal clock’s rhythm.”
You can minimize jet lag before a trip by adjusting your exposure to light before your trip, Dr. Schulman notes. That’s because light is key to resetting your internal clock. If you are going to England from Atlanta, for instance, you can prepare for the six hour time difference by avoiding bright light exposure in the early evening for several days prior to your trip.
Melatonin, a compound the body secretes naturally that helps us fall asleep, is available in synthesized form in supplements and can also help tweak your internal clock and minimize jet lag. (Always talk to your healthcare provider before taking a new supplement or medication.)
“If you are going to England, for example, which is six hours ahead of the Eastern Time zone in the U.S., and your bedtime in London will be 10 p.m. that would be 4 p.m. in Atlanta. So you can start preparing for that shift by taking melatonin around 3 p.m. for a few days before your trip and a few days after you arrive at your destination to help your body adjust,” Dr. Schulman suggests. He adds this strategy isn’t practical if you are flying across time zones towards the west, because you’d have to wake up in the middle of the night to take melatonin in order to adjust to time changes in that direction.
Resetting your internal clock closer to homeYou don’t have to travel to another country to face a change your sleeping schedule. If you have to work at night, for example, Dr. Schulman says your body can adjust – but you’ll need to stick to your sleep-in-the-daytime and be-awake-at-night schedule, even on your days off. Exposing yourself to bright light from a full spectrum lamp for 20 or 30 minutes when you wake up will tell your body it’s time to be alert, even when it’s dark outside. “Then avoid bright light in the hours before you go to bed in the daytime (wearing dark glasses can help) to shift your circadian rhythm,” he adds.
What if you need to get up just an hour earlier than usual to commute to a new office or new work hours? “It should only take a couple of days to adjust to this new schedule. But most people simply think they will get up an hour earlier and they don’t need to go to sleep earlier. That’s not a good idea,” Dr. Schulman states. “Losing an hour wouldn’t be a big deal if most Americans were chronically sleep deprived – but they are. That’s a huge problem and people need to plan better to get enough rest.”
Your individual internal clockHe adds that just as some people need more sleep than others – although most of us do best on 7 and 1/2 to 8 hours of shut-eye a night – it’s important to be aware of your own individual internal clock “settings”. Pay attention to when you feel more energetic and alert and use those times to your advantage.
“There’s really a lot of variability. Some people are morning larks and others are night owls and there are biological underpinnings for that,” Dr. Schulman tells Synergy. “There’s nothing wrong with the speed of your internal clock running a bit differently unless it interferes with your ability to have a social life in the evening or to get to work in the morning.”
|
Sherry Baker is a writer from Atlanta, Georgia. She last wrote the article Should You Go Gluten Free? for Synergy.
