What Science Has to Say About Daylight Saving Time

While there is much talk about the prospect of having longer daylight hours in the evening, few people are mentioning the critical downside that comes with remaining on DST. You may have heard that the loss of the extra hour of sleep leads to an increase in heart attacks, workplace accidents, and car crashes, but you may not realize that some problems persist beyond the day of the switch.

People not getting adequate sleep with wake-up time at 7am Standard

People not getting adequate sleep with wake-up time at 7am Standard

People not getting adequate sleep with wake-up time at 7am DST

People not getting adequate sleep with wake-up time at 7am DST

Many people believe that whenever their schedules change, they can simply adjust their sleep schedule and be perfectly fine after a few days. The problem is that this is just not the case. You see, everyone has a chronotype which is a natural sleep pattern that is biologically determined and persists despite sleep schedule. As you might guess, our bodies don't care about what number is on our computers, cellphones, and watches, they care far more about where the sun is in the sky. This leads us to a very critical problem, DST puts more people out of sync with their chronotype, leading to poor sleep and bad health.

Research published in PLoS ONE used a sample of 53,689 people to examine what an average chronotype really is, and how age and gender play a role in chronotypes. As it turns out, an average chronotype will naturally wake up at about 7am and go to bed around 11pm. When you consider the fact that 7am DST is really 6am Standard time, then you realize that most people are not getting their best sleep during DST. In fact, if you look at the two charts, you will see that with a wake-up time of 7am DST only about 20% of people are getting their best sleep. Research has shown that people with later chronotypes than their schedules permit are already at a higher risk of diabetes, heart disease, and other stress-related illness; even if they are getting the correct total amount of sleep. This means that a switch to DST permanently could lead to increased obesity, heart disease, and diabetes, as well as anxiety and depression.

Considering these factors together, it seems unwise to make DST the year-round standard. If anything we should probably consider staying on standard time and working towards later morning schedules across the board. Research in schools has shown moving schedules later to be incredibly effective in improving performance. So when it comes to whether or not we switch to DST or Standard time permanently, I think we should all sleep on it.

Interested in finding out what your chronotype is? Try this survey to get an idea.