At 2 a.m. on November 4, Americans will “fall back” and gain an hour as we move from Daylight Savings Time to Standard Time. Because the time change occurs in the middle of the night, sleep cycles can be disturbed. New research, published online by German scientists in the October 24 issue of Current Biology, shows that our internal body clocks may not adjust to the change to Daylight Savings Time and instead adjust to the changing cycles of sunlight.
“The body’s clock does not automatically change to the new time, and this is further complicated by our now having four more weeks of Daylight Savings Time,” said Carol Ash, DO, medical director of Somerset Medical Center’s Sleep for Life in Hillsborough, NJ. “Our circadian rhythms are actually set by the sun, and change depending on where we live. We are following the sun’s cycles physiologically. The clock is an artificial creation to allow humans to exist within a social structure, and sometimes time-keeping works against our natural biorhythms.”
The federal Energy Policy Act of 2005 mandated that Daylight Savings Time start three weeks earlier and Standard Time start a week later to reduce energy usage. While this change has had a beneficial effect on energy consumption, it has not been helpful in encouraging good sleep habits.
“It was hard enough for people to adjust before,” said Dr. Ash. “Now, we have abrupt and sudden time changes in the spring and fall. The body doesn’t know how to adapt to these changes overnight.”
In the new study, researchers collected data on the sleep patterns of 55,000 Europeans. The researchers found that the time period that study subjects slept on their weekends during Daylight Savings Time still followed the seasonal progression of dawn under Standard Time, not the Daylight Savings Time progression. Their internal clocks did not automatically adjust and followed the sun rather than the clock.
“In looking at this study, it is clear that nature doesn’t have an 'on/off' switch, says Dr. Ash. “People who tend to either go to bed unusually late or get up very early will be the most affected when the clocks change.”
While these changes are disruptive of sleep patterns – especially in the shift to Daylight Savings Time – there are some things people can do to minimize the effects of this weekend’s time change.
Dr. Ash suggests:
- Maintain your regular bedtime Saturday night and awaken at your regular time. This can give you an “extra” hour of sleep the next morning and help reduce your sleep debt.
- Block out light and keep your sleeping area dark. Standard Time means sunrise will occur about an hour earlier. This can impact sleep, especially for people accustomed to awakening before or around sunrise. The light itself also can disturb sleep. It is always best to sleep in a darkened room until you wake up.
- Increase the light when you wake up. Light has an alerting affect that may help you wake up. It also will help adjust your biological clock to the “new” sleep schedule.
- If you are a “night owl” and tend to be wide awake and energetic until late and night and sleepy in the morning, start a week ahead; a gradual delay in bedtime and awakening a few days before the time change may help you adjust to the change.
- Difficulty adjusting to the time change – staying awake at night or sleeping until your desired wake up time may be helped by gradually moving bedtime and awakening later by 15 minutes every one to two days.