Daylight Saving: "Spring Forward" Isn't the Only Reason You Feel Tired

Don't blame "spring forward" for your confused circadian rhythm.

On Sunday, the clocks in the United States will suddenly jump forward one hour because of daylight saving time. It will mark the first of two days each year that we bemoan its most widespread — and worrisome — effect: a disruption in our internal clocks. But our body clocks are already messed up, even when we’re not springing forward or falling back.

Pushing the clock forward ever so slightly messes with the cycle of light and darkness that controls our circadian rhythm, the natural 24-hour cycle controlling our body’s processes, like setting its temperature and releasing the hormones that make us hungry, tired, or energized. One hour is a big deal: Springing forward results in more light in the afternoon and less light in the morning, disrupting the pattern that our biological clocks have become accustomed to. What we end up with is a mismatch between our biological internal clocks and the social clock that governs our lives.

Desynchronization is linked with many health consequences: a 2016 study in Sleep Medicine reported an 8 percent increase in strokes the Monday after daylight saving time, and another in Open Heart published in 2014 noted a ten percent increase in heart attacks. Studies like these have led some states, like Maine and Washington, to consider ending the tradition for good.

But even if we do, many other aspects of modern society still have the potential to upset circadian rhythm. If we’re in search of ways to encourage circadian harmony, it might be worth rethinking some of our other habits, too.

On March 10th the clocks will jump forward and disrupt circadian rhythms 

Lauren Rushing/Flickr

Our Internal Clocks Aren’t Just Messed Up Twice Per Year

Factors like screen exposure, societal demands, and the constant 24-hour glow of artificial light don’t subside once daylight savings time ends, continuing to shift the body clock.

Constant exposure to the blue light from screens, for example, has been shown to upset the cycles of hormone release that are typically governed by light-dark cycles.

A 2017 study in Current Biology argued that modern environments where artificial lights are constantly on pushes our “biological night” later into the evening. And in 2018, a Cell paper revealed that the average American lives their life roughly 75 minutes out of sync of their preferred rhythm.

Michael Rust, Ph.D., that paper’s author and a University of Chicago biologist, previously toldInverse that the 75-minute “social jetlag” he discovered using Twitter data was due to work schedules that force people to forsake their internal clocks.

“If you don’t have to set an alarm clock, then that clock will give the body signals to wake up and go to bed at certain times,” he said. “It’s now possible for people to work schedules that are in conflict with their internal rhythms.”

Constant artificial light can also mess with our internal clocks. 


Can You Change Your Circadian Rhythm?

Scientists have discovered activities that can help some people wrest control of the circadian clock to better fit society’s schedule of waking and sleeping. Exercising within certain time intervals or spending a weekend in the woods) away from artificial light, for example, can help shift the sleep-wake cycle back or forward by up to 30 minutes. But unfortunately, recent research underscores the key role of genetics in circadian rhythm, suggesting that to some extent, the body clock is pretty inflexible.

A paper published in January in Nature Communications showed that there are roughly 351 different genes that influence a person’s preferred wake-up time — sometimes by as much as 25 minutes. Historically, these genes have also been used as indicators that separate “morning larks” from “night owls.”

University of Exeter research fellow Samuel Jones Ph.D., the study’s lead author, explained that these genes actually affect how someone’s brain may interpret light-dark signals that govern the internal clock.

“Our work indicates that part of the reason why people are up with the lark while others are night owls is because of differences in both the way our brains react to external light signals and the normal functioning of our internal clocks,” Jones said.

The genetic aspect of the internal clock works out badly for “night owls,” whose natural rhythm clashes with the demands of a typical workday.

Night owls may feel more productive at night because of biological factors, but they still have to conform to a 9-5 work schedule. 


A small study on 38 people in the journal SLEEP found that these circadian genes actually influence brain activity and also turned up bad news for night owls. The team, led by University of Birmingham researcher Elise Facer-Childs, Ph.D., showed that the “morning larks” had higher functional brain connectivity during the day, which was associated with higher alertness, and attention. Night owls, in turn, had lower functional connectivity during the day, and reported sleepiness or even slower reaction time.

The pattern of brain activity seen in the latter group might represent an “intrinsic neuronal mechanism, which leads to ‘night owls’ being compromised during a normal working day,” the authors wrote. In short, it might be that no amount of sleep-shaming, daylight saving, exercising, or exposure to natural light will help them realign their internal rhythms to conform to society’s clock.

Fixing Circadian Health Beyond DST

While efforts to end seasonal clock changes could have an impact on circadian health, plenty of other societal changes could create more lasting circadian harmony.

University of Colorado, Boulder integrated physiologist Kenneth Wright, Ph.D., lead author of the 2017 Cell study on artificial light mentioned above, has said that changes to architecture that embrace natural light instead of artificial light could be one way to tackle our constantly misaligned clocks.

Creating a workday to accommodate for night owls or allowing for more flexible work schedules, Facer-Childs previously told Inverse, could also improve the health of employees.

“I believe that accounting for individual differences in sleep patterns and body clocks could open up a relatively untapped source, [and] could contribute to being at our best, both mentally and physically,” she said.

Their research suggests that we do the opposite of daylight saving time — that is, start thinking about how we can work with our biological clocks instead of against them. The historical rationale for daylight saving time was to give the public more time to enjoy the sunlight after a 9-to-5 workday, but as we better understand the demands of individual circadian rhythms and the effects of modern technology, maybe now is the time to factor in more flexibility.

Health-concerted efforts to stop pushing the clocks forward and backward may be just the first wave of realization that our biological clocks aren’t something worth bending to political will. Hopefully, that realization will tackle far more ubiquitous threats to circadian health than the hour of time change that happens twice per year.

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