Shift to Daylight Saving Time Can Disrupt Sleep
The "spring ahead" to daylight saving time the second Sunday in March can cause real, if short-lived, sleep disorders that even show up in highway crash statistics.
David Plante, MD, a Wisconsin Sleep physician who specializes in sleep disorders, explains that the lost hour of sleep when clocks are set ahead can disrupt two key physiological drives that control our sleep: our circadian rhythms and our sleep homeostat, which keeps track of our "sleep debt."
"Both the spring and the fall time changes can cause sort of a temporary jet lag, as if we suddenly stepped off a plane one time zone away," says Plante, an assistant professor of psychiatry at UW School of Medicine and Public Health.
"It's the spring time change that tends to make people the most miserable because people find it more difficult to deal with that lost hour of sleep,'' says Plante. "Although most people adjust in a day or two, it can take some people up to a week to get used to the time change."
For most, the lost hour of sleep is just a mild disruption, but on a population basis, it can be fatal. A Stanford University study looked at 21 years of traffic data and concluded that the spring shift is associated with a small but significant increase in the number of fatal accidents on the Monday following the time shift.
Plante says that some people are more strongly affected by the time shift, including people with sleep disorders such as sleep apnea, psychiatric problems such as bipolar disorder, shift workers whose circadian rhythms are already disrupted, and others who are chronically sleep-deprived.
Plante says there are several things you can do to cope with the lost hour of sleep:
- If you tend to sleep in on the weekends, avoid doing this on the Saturday before the time changes, so you're ready to go to bed earlier that night
- Expose yourself to bright light in the morning when you first wake up to help reset your circadian clock
- Avoid caffeine after noon and avoid alcohol close to bedtime
- Get rigorous exercise several hours before bed
- Avoid scheduling important appointments first thing Monday morning, so you're not rushing while already sleep-deprived
Interestingly, the Stanford study showed that the fall shift is also associated with more accidents on the Sunday morning following the "fall back" time shift in October. They concluded that these were due to behavioral, rather than physiological causes: the extra hour before closing time kept people out later, possibly causing them to drink more alcohol and drive when they were sleepy or impaired.
Date Published: 03/03/2011