Daylight Saving Time and Sleep

Daylight Saving Time and Sleep

Still struggling with sleep after daylight saving shifts? As it turns out, jet lag and time zone changes aren’t the only shifts that can disrupt our sleep schedules! Daylight saving shifts, which occur twice a year for most of the continental US, have been found to impact our health, sleep, focus, and more. These biannual time switches have been linked to increases in workplace injuries, sleep disturbances, strokes, heart attacks, car accidents and fatal car accidents, and other issues.

That means twice a year, our circadian rhythms and biological clocks have to catch up to the new time changes, causing many physical health problems and other risks for many Americans.


But first– is it daylight saving or daylight savings?

While saying daylight savings might sound more natural to many, it’s actually daylight saving time! The practice involves “saving” daylight so we’re not spending more of our waking hours in the dark. 



So, what is daylight saving time?

The practice of daylight saving involves a biannual time shift that moves the clocks an hour ahead in the spring, and sets our clocks back an hour again in the fall. The practice has been in place since the 1960s in most US states. Come spring, daylight saving time gives us more hours with light in the evening, and in autumn when we “fall back,” we get more daylight hours in the mornings. Daylight saving time is also noted in time zone designations, e.g. at Kin Slips HQ in California, our fall and winter are mostly in Pacific Standard Time, or PST, while spring and summer are spent in Pacific Daylight Time, or PDT. 


How does daylight saving time affect our overall health?

According to research by the National Institutes of Health, at least 150,000 Americans reported physical health problems as a result of daylight savings. Research has also shown that strokes, heart attacks, accidents, and changes in mood can all occur as a result of daylight saving shifts. 

Our biological clocks are set and regulated by our exposure to the sun, and its absence. Our metabolism, hormone production and release, blood pressure, and more are all affected by the sun and our biological clocks. These bodily functions can impact and influence mood, alertness, focus, hunger, energy levels, sleep, and more! Instances of depression and increased mental health issues have also been associated with daylight saving shifts, which we dive deeper into below.



How is sleep affected by daylight saving?

For many, it can be hard to adjust to falling asleep and waking up an hour later or earlier than our bodies were used to for ~6 months. Not only does daylight saving time change the clocks on us, it changes the amount of sun we’re able to get, which impacts the production of many naturally occurring hormones in our bodies and brains. 

When we’re exposed to sunlight, the sun’s rays trigger our brains to release serotonin, a hormone that boosts our moods, and helps us feel more calm, focused, and simultaneously more alert. Melatonin is released naturally by our bodies at night in response to the absence of sunlight, making us tired and signaling to our bodies that it is time to rest and sleep. When we’re exposed to light, the production of melatonin is stopped by our pineal glands, encouraging us to become alert and stay awake.

Melatonin is most significantly associated with regulating our sleep-wake cycle. Melatonin levels can also change following the time shifts, and the disruption of our body’s melatonin production and levels play a serious role in regulating our sleep patterns and moods. In addition to ruling our sleep-wake cycles, melatonin also helps regulate blood pressure levels, body temperature, cortisol levels (also known as the stress hormone), and immune function.



What other issues are tied to daylight saving time shifts?

Did you know daylight saving time corresponds with an increase in fatal car accidents, workplace injuries, depression, strokes, and heart attacks every year? Research has found that fatal car accidents increase by 6% the week following biannual time changes. Because daylight saving shifts can increase sleep deprivation, we see more instances of drowsy driving, as many drivers may not even be aware of their own exhaustion levels. 

Less hours of sunlight lead to reduced levels of serotonin, which can trigger depression for many who struggle with mental health issues, including depression, and seasonal affective disorder, also known as SAD, or seasonal pattern depression. Serotonin levels have a large effect on our moods, and can significantly decrease following the end of daylight saving time in the fall. A study from 2016 titled “Daylight Savings Time Transitions and the Incidence Rate of Unipolar Depressive Episodes” found that the transition from daylight time to standard time was associated with an 11% increase in the incidence of unipolar (also known as Major depression) depressive episodes.


So why do we do daylight saving time anymore anyways?

If all this information has turned you off daylight saving, you’re not alone. In fact, you’re due for some good news finally! 2023 might be the last year for daylight saving time shifts, as The U.S. Senate recently approved a bill to make daylight saving time permanent!

In March of 2022, the Senate passed legislation that would make daylight saving time permanent in 2023, meaning when we “spring forward” in March, we may not have to fall back again next November! The Sunshine Protection Act was approved unanimously in the Senate, but the bill must pass in the House, before it can be signed into law by President Joe Biden. Things are looking optimistic for permanent daylight time, as lawmakers cited one 2019 poll which reported 71% of Americans would prefer to end the decades-long tradition of switching our clocks twice a year.



So if you’re feeling groggy, depressed, drowsy, or down about daylight saving time, find comfort in the fact that this might be our last full year of time shifts. It’s important to pay extra attention to your sleep habits, sleep hygiene, energy levels, mood, and overall wellbeing following daylight saving time changes. If you’re having trouble with shaking these differences, remember daylight saving time changes affect our circadian rhythms, metabolism, hormones, blood pressure, and more elements that affect more than just our sleep, focus, and lives.

If you’re having trouble with your mental health, try reaching out to friends or family, or consider calling SAMHSA’s national helpline for individuals and families facing mental health disorders.