Daylight saving time advances the clock by one hour during warmer months so that darkness falls at a later time. Along with the ritualistic custom of resetting the clock on the microwave, daylight saving time also causes you to lose an hour of sleep. 

Although losing one hour of sleep might not seem like much, the cumulative effects of sleep deprivation can impact your health more than you think. 

Daylight Saving Time Affects the Body's Master Clock

Daylight saving time increases your morning exposure to darkness and evening exposure to sunlight. This disrupts your "internal clock," which can impair your sleep cycle and other bodily functions. 

This so-called master clock in the brain coordinates the various biological clocks in your body, keeping these clocks in sync. The master clock is a group of approximately 20,000 nerve cells that form a structure called the suprachiasmatic nucleus (SCN) in a part of the brain called the hypothalamus.1  

This body clock controls when you're awake and when you're ready for sleep. This 24-hour repeating rhythm – called the circadian rhythm – is in sync with environmental cues, such as daylight and darkness. The light received through your eyes (even through closed eyelids during sleep) stimulates a signal that travels to the SCN, telling your brain that it's daytime.1,2 

Your internal master clock also controls the release of chemicals in a daily rhythm. As the sun rises, the body releases cortisol, a hormone that naturally prepares you to wake up. When it gets dark, the body releases melatonin, a hormone that helps you feel drowsy and signals your body it's time to sleep.1,3

During daylight saving time, the sun lights the sky for a longer period during the evening hours – which affects the biological processes that prepare your body for sleep – and why you might feel groggy when the clock moves forward an hour each Spring.

How Losing Sleep Affects Your Body and Behavior 

Sleep essentially "reboots" your entire body. It has a restorative effect, particularly on the immune, endocrine, and nervous systems. Sleep also keeps your brain functioning so you can think clearly and focus.3,4 

There are many benefits to practicing good sleep health, as well as several risks for cutting sleep too short. When you sleep fewer hours than your body needs, you have a sleep debt, also called a sleep deficit. The recommended amount of nightly sleep for adults is 7-9 hours. Yet more than one-third of U.S. adults report getting fewer than seven hours of sleep nightly.5-7 An adult who gets six hours of sleep nightly for five nights has a sleep debt that ranges between 5-15 hours. As a sleep deficit builds, brain and body functions can deteriorate. 

According to a recent small study, individuals in their 20s who slept 30-percent less than they needed for 10 nights didn't fully recover their cognitive processing, even after seven nights of unrestricted sleep.8

A 2017 study found that healthy middle-age adults who slept poorly for one night showed a significant increase in the amyloid beta peptide9 – a component of amyloid plaques characteristic of Alzheimer's disease.10

In the short-term, sleep deficiency can cause problems with learning, focusing, and reacting. You might have trouble making decisions, solving problems, remembering things, controlling your emotions and behavior, or coping with change.3,4 

Long-term sleep deficiency is linked to many chronic health problems, including heart disease, kidney disease, high blood pressure, diabetes, stroke, obesity, and depression.3,4

Can't I Sleep in to Make Up for Lost Sleep?  

Making up for lost sleep isn't as straightforward as "sleeping in." Nor is it a matter of “paying back” a sleep deficit with an hour of sleep for every hour of lost sleep. The key lies in getting the length of sleep you need to feel rested when you awaken. This includes getting enough of each type of sleep: rapid eye movement (REM) sleep and non-REM sleep.

Generally, REM and non-REM sleep occur in a regular pattern of 4-6 cycles each night. Dreaming typically occurs during REM sleep. Non-REM sleep includes what's commonly called deep sleep or slow-wave sleep. Your ability to function and feel well while you're awake depends on whether you get enough total sleep and enough of each type of sleep. It also depends on whether you're sleeping at a time when your body is prepared and ready to sleep.3,11,12

Tips to Manage the Transition to Daylight Saving Time

If you find yourself feeling sleepy after the change to daylight saving time, then try these tactics to adjust your mind and body to the adjusted clock time.13

  1. Go to bed 15 minutes earlier each night. Do this every couple of nights until you reach your desired bedtime. 
  2. If you're sleepy, then take a short 15-20 minute nap in the early afternoon – but not too close to bedtime.
  3. Assess how a nap affects your sleep quality. For some, napping can make nighttime sleeping more difficult. For others, a short nap is revitalizing and doesn't affect nighttime sleep. 
  4. Reduce exposure to bright artificial light in the late evening from TV, phone, and computer screens. The light interferes with your body's internal clock, making it harder to fall asleep.14 
  5. Once you've acclimated to the time change, be sure to go to bed and wake up at the same time each day. This helps your body regulate its sleep. 

Getting adequate sleep is as important to your body as breathing and eating. As the weather warms and the days lengthen, be sure to make getting a good night’s sleep a priority to benefit your mind and body.

A Note from Thorne

If something is disrupting your sleep, then consider Thorne’s easy at-home Sleep Test, which provides insights into your cortisol and melatonin levels, both of which can be affected by disruptions in your circadian rhythm. Or consider a nutritional supplement that safely supports restful sleep. Not sure which supplement might be best for you? Thorne’s easy-to-take sleep quiz will guide you to the best choice.


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  2. Circadian rhythms and circadian clock. The National Institute for Occupational Safety and Health. [Accessed Feb 24, 2022]
  3. Sleep deprivation and deficiency: National Heart, Lung and Blood Institute. [Accessed Feb 24, 2022]
  4. Cirelli C. Definition and consequences of sleep deprivation. [Accessed March 1, 2022]
  5. Sleep and sleep disorders – data and statistics: Centers for Disease Control and Prevention. [Accessed Feb 24, 2022]
  6. Sleep and sleep disorders – how much sleep do I need? Centers for Disease Control and Prevention. [Accessed Feb 23, 2022]
  7. Sleep debt: The National Institute for Occupational Safety and Health. [Accessed Feb 23, 2022]
  8. Ochab JK, Szwed J, OleĊ› K, et al. Observing changes in human functioning during induced sleep deficiency and recovery periods. PLoS One 2021;16(9):e0255771.
  9. Ju YS, Ooms SJ, Sutphen C, et al. Slow wave sleep disruption increases cerebrospinal fluid amyloid-β levels. Brain 2017;140(8):2104-2111. 
  10. Rukmangadachar LA, Bollu PC. Amyloid beta peptide. 2021. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. PMID: 29083757. 
  11. Brain basics understanding sleep: National Institute of Neurological Disorders and Stroke. [Accessed March 1, 2022]
  12. Patel AK, Reddy V, Araujo JF. Physiology, sleep stages. [Updated 2021 Apr 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan.
  13. How to manage daylight saving time. Mayo Clinic. [Accessed March 1, 2022]
  14. Grandner M, Lang Gallagher R, Gooneratne N. The use of technology at night: Impact on sleep and health. J Clin Sleep Med 2013;9(12):1301-1302.