The Time Change: How Does it Affect Our Health?

The time change can increase the risk of heart attacks, mental illness, and accidents. We show you how else it can affect your health, as well as how to counteract it.
The Time Change: How Does it Affect Our Health?

Written by Daniela Andarcia

Last update: 06 July, 2021

In many countries, our clocks either go back or forward to allow for the transition to and from daylight saving time (DST). The truth is that about a quarter of the world’s population is affected twice a year by this time change.

Advancing an hour in spring as we enter summer, means we lose an hour’s sleep, and alters our work and rest times. According to a study published in PLOS Computational Biology, it’s possible for the body’s biological clock to change as well. Discover other ways in which the time change can affect your health.

How does the time change affect health?

The time change can be conflicting.
The time change can affect both physical and mental health.

As we have seen, advancing one hour to daylight saving time during the spring means we lose an hour’s sleep. Although many think that it doesn’t seem like much, it can actually affect health in several ways.

According to a survey by The American Academy of Sleep Medicine, more than half of Americans tend to feel tired after the onset of daylight saving time. Let’s look at other effects of the time change:

1. It increases the risk of having a heart attack

According to a study published in the medical journal Open Heart, daylight saving time increased the risk of having a heart attack by 24 percent the next working day.

In addition, the same study found that when the time returns to normal and people have one more hour of sleep, the risk of experiencing a heart attack decreased by 21 percent on the Tuesday following the time change.

Research presented at the 2016 American Academy of Neurology conference found that time changes during DST increase the likelihood of having an ischemic stroke or stroke.

2. It can trigger mental illness

Experts believe that missing an hour of daylight during the afternoon due to daylight saving time can lead to mental illnesses such as depression, seasonal affective disorder (SAD), and even bipolar disorder.

Research published in Epidemiology showed that cases of depression increased by 11% after the time change, gradually dissipating, but lasting up to 10 weeks.

Similarly, a study published in Sleep and Biological Rhythms proved that there was an increase in male suicide rates in the days following the change of daylight saving time in the spring and fall.

3. It can affect mood

Just as the time change and lack of sleep can be responsible for mental disorders such as depression, they also have negative effects on mood, increasing anxiety, irritability and mental exhaustion.

Also, if you have teenagers at home, summer time can affect them even more, as they require more sleep.

4. It increases the probability of having an accident

Losing an hour of sleep not only alters your mood, it can also affect your cognitive performance by becoming confused and slowing you down, making you more prone to accidents.

A 2001 study that looked at 21 years of data on fatal car accidents found a small but noticeable increase in car crash deaths on the Monday after the start of daylight saving time in the spring.

The result was 83.5 deaths compared to 78.2 deaths on average on Mondays.

Something similar happened with accidents at work. Research published in the Journal of Applied Psychology showed that on Monday after the daylight saving time change was implemented, there was a 5.7% increase in workplace injuries and almost 68% work days lost due to injuries, which indicates that they were serious.

5. It may cause miscarriages

The time change can affect pregnant women.
Although unlikely, some obstetric complications can arise.

According to a study published in Chronobiology International, miscarriage rates in IVF patients were significantly higher after the start of spring DST.

How does returning to normal hours affect health?

Just as losing an hour of sleep harms your health, getting back to normal can have some benefits:

  • Reduces the rate of heart attacks. According to a study published in The New England Journal of Medicine, the heart attack rate dropped on the Monday after daylight savings time ended in the fall.
  • Reduces the number of car accidents. Another study published in The New England Journal of Medicine found a reduction in the number of car accidents after the end of daylight saving time in the fall.

What tips should you follow to adjust to the time change?

To mitigate the effects of the daylight saving time change, consider the following recommendations:

  • Adjust your biological clock. If you start getting up earlier than usual a week earlier, it will be easier for you to do it on that first Monday morning, as well as the rest of the days.
  • Eat a healthy breakfast first thing in the morning. Food tells your body that the day has started!
  • Exercise in the morning. Exercise in the morning not only exposes you to light, which is essential to adjust to the change, but it also helps you wake up, increases body temperature and starts the day with more energy.
  • Don’t drink too much caffeine. It’s no problem if you have a cup of coffee in the morning. However, don’t alter your habits due to the time change by drinking extra coffee in the afternoon.
  • Don’t take naps. Even if the time change makes you feel more tired, don’t take naps, this will only prevent you from sleeping through the night and, therefore, make the situation worse.

The time change can have serious consequences

Daylight saving time is usually one hour ahead, causing you to lose out on an hour of sleep. This, in addition to causing a lack of sleep, alters the biological clock and, in turn, can trigger a series of diseases and health problems.

Among them, as we’ve seen, are an increased risk of heart attacks, mental illness and accidents, as well a negative effect on your mood. Fortunately, you can adjust to summer time with lifestyle changes like eating breakfast first thing in the morning and avoiding coffee and naps.

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  • Sandhu, A., Seth, M., & Gurm, H. S. (2014). Daylight savings time and myocardial infarction. Open heart, 1(1), e000019.
  • Hansen, B. T., Sønderskov, K. M., Hageman, I., Dinesen, P. T., & Østergaard, S. D. (2017). Daylight Savings Time Transitions and the Incidence Rate of Unipolar Depressive Episodes. Epidemiology (Cambridge, Mass.), 28(3), 346–353.
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  • Liu, C., Politch, J. A., Cullerton, E., Go, K., Pang, S., & Kuohung, W. (2017). Impact of daylight savings time on spontaneous pregnancy loss in in vitro fertilization patients. Chronobiology international, 34(5), 571–577.
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