Daylight Saving Time: The Effects of Losing an Hour of Sleep

We all complain about losing an hour of sleep when spring comes around, although we enjoy the days staying light longer. Of course, which of us actually get 8 hours of sleep every night anyway, right? So what is the big deal about daylight savings time? The dangers may be more than you imagined – there is a big difference between losing an hour of sleep and actually losing an hour.

All creatures have biological cycles including humans – these cycles are called circadian rhythms. The hypothalamus is the portion of the brain responsible for keeping track of this cycle. Using cues such as the sun, your body releases hormones and other chemicals at specific times during a 24 hour period, thus enabling you to sleep and perform other necessary tasks at the right time.

It makes people 40 percent more likely to have a heart attack first thing in the morning, since blood pressure is rising, heart rate increases, and blood vessels dilate all in an effort to help you wake up. It makes running outside to shovel heavy snow first thing in the morning one of the most dangerous things a middle-aged person can do.

What does this have to do with turning the clocks forward in the spring? Well, it throws off our circadian rhythm – the body simply isn’t yet ready to wake up, and needs to get going before it’s ready. Heart attacks increase by at least 5 percent in the days following the time change. In fact, researchers suggest starting a few days early and adjusting the clocks by quarter of an hour per day to give your body a chance to adjust. Also, don’t perform strenuous activities the first few mornings after making a change like this.

Traffic accidents also increase with lack of sleep. There are several reasons for this – one may simply be that people are in a hurry because they’ve forgotten to reset their clocks and are running late; another possibility is that commuters may suddenly have to adapt from driving in the light in the morning and dark in the evening, to driving at either sunrise or sunset, the two times of day that affect vision the most.

Most importantly, it goes back to the normal biological cycle again – the body simply isn’t awake yet, and a person’s driving, especially in the morning when they are not fully alert, is affected. It can also make a person more tired at night since they probably feel as if they had woken up earlier than they actually did.

Clearly, the effects of daylight savings time amount to more than just the loss of an hour of sleep – so please exercise caution when your schedule has to make a jump like this.

By Eric Cohen, MD