Daylight Savings Time & Your Health
Millions of Americans welcomed an extra hour of sleep this past weekend as they turn back their clocks for the end of Daylight Savings Time. But the time change may take a toll on health in a number of ways. Changing to daylight saving time may give people an hour less more of sunlight, but it appears that their internal body clocks never really adjusts to the change, German researchers report. In fact, daylight saving time can cause a significant seasonal disruption that might have other effects on our bodies.
People’s circadian rhythm — the body’s internal clock — follows the sun and changes depending on where you live. It actually changes in four-minute intervals, exactly the time it takes for the sun to cross one line of longitude. The circadian clock does not change to the social change. During the winter, there is a beautiful tracking of dawn in human sleep behavior, which is completely and immediately interrupted when daylight saving time is introduced in March. It returns to normal this year when standard time returns on Nov. 4. Daylight saving time may be one cause of our lack of seasonality. By seasonality,it means that our internal clock is in tune with the natural change in light throughout the year. This could have long-term effects.
Transitions associated with the start and end of DST disturb sleep patterns, and make people restless at night, which results in sleepiness the next day, even during a “Fall back” period, since when we Fall Back, we might have trouble adjusting to going to sleep “later” after the time change. This sleepiness leads to a loss of productivity and an increase in “cyberloafing” in which people muck around more on the computer instead of working. The debate still rages as to if this time-switch does save energy, but along the way we’ve seen signs that it has negative effects on our health and the economy.
During the first week of DST (in the late winter) there’s a spike in heart attacks, according to a study in the The American Journal of Cardiology (and other previous studies). That’s because losing an hour of sleep increases stress and provides less time to recover overnight. The opposite is true when we gain an extra hour of sleep. The end of daylight saving time causes a decrease in heart attacks. Still, not all studies show the negative side of DST. Light dictates how much melatonin our bodies produce. When it’s bright out, we make less. When it’s dark, our body ramps up synthesis of this sleep-inducing substance. Like anytime you lose sleep, springing forward causes decreases in performance, concentration, and memory common to sleep-deprived individuals, as well as fatigue and daytime sleepiness.
If you find yourself struggling to adjust year after year, try this strategy the next time around: Starting on the Friday before the fall transition, take .3 milligrams of melatonin — you may have to cut up a tablet to get such a small dose — when you wake up; do this through the Monday after the time change. Melatonin is a chemical dark signal. It shifts the body clock later and counteracts the effect of morning light. This tiny dose probably isn’t enough to make you drowsy — but it will help your body adjust more quickly to the change.