Fast Forward to Spring, Slowly Fall Back to the Normal Heart

As the days become longer and the weather gets warmer, it’s that time of year again. Daylight saving time has been observed in most parts of the United States, and it’s time to manually set the clock one hour forward. When the clocks go forward, we ‘lose’ one hour of sleep. Even you try to compensate by forcing yourself to sleep more, your body might not follow your brain’s instructions due to the constant biological clock system, circadian rhythms. In a simple way, sudden disruption of sleep schedule could cause sleep deprivation and misalignment. The consequences of sleep disruption could have profound impacts, especially on cardiovascular health.

Why do we have daylight saving time?

In the United States, it’s scheduled to be the second weekend of March. In the European countries, the daylight saving normally is on the last weekend of March in spring. The idea is pretty much the same. The origin of daylight saving dated back to 1784, Benjamin Franklin proposed to adjust clocks for economic reasons. About 130 years later, Great Britain started to enact the daylight-saving rule to reduce energy costs during the war. Other countries then followed suit.

What are the health consequences?

One of the main consequences of forwarding one hour of clocks is sleep disruption. Despite the common opinion that shifting one hour of sleep ahead is inconsequential, increased sleep fragmentation and sleep latency present a cumulative effect of sleep loss at least across the following week, possibly longer (1). Circadian rhythms, commonly known as the internal clock, can directly or indirectly regulate many important biological functions such as sleep and locomotor activities, feeding and drinking behavior, core body temperature, endocrine activity, metabolism, autonomic and sympathetic activity, and many others (2).

What can we do to mediate the effects?

In 2020, the American Academy of Sleep Medicine published a statement calling for the abolition of daylight saving (3). It discussed acute and chronic harmful effects of sudden transition of sleep schedule attributed to daylight saving. The academy said, “the shift, by disrupting the body’s natural clock, could cause an increased risk of stroke and cardiovascular events, and could lead to more traffic accidents”. A call for permanent daylight saving time has been advocated and discussed both in European countries and in the United States. Just recently, United States senates approved a bill to make daylight saving permeant, the Sunshine Protection Act. Whether it will get approved by the House of Representatives and President Joe Biden, it’s still unknown.

At the moment, there are a few approaches to facilitate a smooth transition to the spring season. Common practices of good sleep hygiene such as avoiding caffeine and alcohol consumption late at night, following a consistent sleep schedule, using relaxation techniques to facilitate a stress-free sleep, avoiding screen exposure before bed, avoiding eating too close to bedtime would be some good starts. It’s also recommended to adjust clock time gradually to the daylight saving time a few days before and increase morning sun exposure to facilitate internal clock re-adjustment after daylight saving. Don’t expect your body can suddenly adjust to a new time schedule, treat it like jet lag. Allow some time for your body to recover and take it slowly to be your normal self.


  1. Manfredini, R., Fabbian, F., Cappadona, R., & Modesti, P. A. (2018). Daylight saving time, circadian rhythms, and cardiovascular health. Internal and Emergency Medicine, 13(5), 641–646.
  2. Young, M. E., & Bray, M. S. (2007). Potential role for peripheral circadian clock dyssynchrony in the pathogenesis of cardiovascular dysfunction. Sleep Medicine, 8(6), 656–667.
  3. Rishi MA, Ahmed O, Barrantes Perez JH, et al. Daylight saving time: an American Academy of Sleep Medicine position statement. J Clin Sleep Med. 2020;16(10):1781–1784.


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