Daylight Saving Time (DST) is almost here — and springing forward can have a profound impact on your health.
This year, on Sunday March 10th, the clocks will jump from 1:59 a.m. to 3:00 a.m. – skipping an entire hour and making us all lose an hour of sleep (unless you live in Hawaii, parts of Arizona, or one of the many countries that do not observe DST).
But what is the purpose of moving our clocks, and does it have a negative impact on our health?
Daylight Saving Time was implemented to give us all an extra hour of daylight for around eight months of the year. DST doesn’t actually extend the total amount of daylight, it just “takes” an hour of daylight away from the morning and “gives” it to the evening. But for the average person, this boils down to one thing: On the days we change the clocks, every autumn we “gain” and hour of sleep, and every spring we “lose” an hour of sleep.
Losing an hour of sleep may just seem like a pesky annoyance, but research has shown that this time change can actually impact your health.
It disrupts your sleep cycle.
Everybody’s sleep/wake cycle is determined by their circadian rhythm. The circadian rhythm, in turn, is impacted by light and darkness. Because DST changes what time it becomes dark, it takes time for your circadian rhythm to adjust. Think of this as being similar to when you travel to a new time zone and get jet lag. Typically, it takes your circadian rhythm one day to adjust for every hour the time changes. Using this model, it should take your body one day to adjust to DST. Which means that for that one day, you may feel more fatigued or more alert than usual. Getting one less hour of sleep may make you more tired the following day, and studies show that this sleep fragmentation may have an impact across the following week. Sleep deprivation in general can lead to other problems, like decreased alertness. Some studies have shown that in the days after the time change, road traffic accidents increase.
Serious health risk?
Studies have shown there are some lesser-understood impacts of DST. For example, the day after the springtime change, an increased number of heart attacks are reported, but the total number of heart attacks during the entire week does not increase. Similarly, there is an increased risk of stroke in the first two days after DST begins, but when looking at the total number of strokes in the week, there is no change.
So, what do you need to know to prepare for this time change?
The most important thing you can do is to always practice good sleep hygiene. This includes going to sleep and waking up around the same time every day, avoiding eating in the hours before bedtime, and avoiding screens or other blue lights in the hours before you sleep. On the day of the change, to avoid sleep deprivation, it is helpful if you sleep in an hour, so you are still getting a full night of rest.
If you are working or are otherwise unable to sleep in an extra hour, you may want to consider gradually adjusting your body to the time change by 15 minutes every day during the days prior to the change. Lastly, look out for signs that you might be sleep deprived and be aware of the symptoms of heart attack or stroke. If you feel unsafe or suspect you may be experiencing an adverse health impact, seek medical attention immediately.