Mar 10, 2024 - News

Daylight saving time is back. Here's what that means for Denver.

Illustration of a person's arm wearing a wristwatch with the face made from a sun.

Illustration: Annelise Capossela/Axios

On Sunday, we "spring ahead" to daylight saving time, even though many sleep experts β€” including in Colorado β€” wish we wouldn't.

Why it matters: Members of health groups and organizations like the Colorado Sleep Institute tell us they favor standard time because it's more aligned with our body clocks.

State of play: Colorado passed a bipartisan bill in 2022 that would end the seasonal time shifts in the wake of similar moves in the U.S. Senate β€” but it's far from becoming a reality. That's because the law was written with two big caveats:

  • It would only be enacted if the federal legislation is approved, but efforts remain stalled.
  • Additionally, at least four other states in the Mountain Standard Time zone would have to adopt similar bills, yet only three have: Utah, Wyoming and Montana.
States with year-round daylight saving time trigger laws
Reproduced from NCSL; Map: Axios Visuals

Zoom in: Starting Sunday, Denver's sunrises will change from 6:23am to 7:23am and sunsets will move from 6pm to 7pm, with both gradually coming later.

What they're saying: "We're going to go basically to the Central Time zone this weekend, but our sun is still going to be on Mountain Time," creating a "disconnect," Ellen Stothard, research and development director at the Colorado Sleep Institute, tells us.

  • "It's not a natural thing for your body to be in that misalignment for a consistent period of time," she explains.

Threat level: "Research shows that the abrupt seasonal shift in time disrupts circadian rhythms, leading to sleep disturbances, increased fatigue and even a heightened risk of heart attacks and strokes," says James Rowley, president of the American Academy of Sleep Medicine.

  • He adds that right after the clocks shift in March, there's "a spike in workplace accidents, road accidents and medical errors due to sleep deprivation and cognitive impairment."

Between the lines: With the latest time change, daylight is not "saved" per se, but it is shifted to remain later in the evening.

  • In spring and summer, days are naturally longer than they are in the fall and winter (when we're on standard time), regardless of time zone.

To avoid the abrupt hour of sleep loss today, experts recommend that you:

  • Create a routine. "You will be less affected if you have a routine and you're able to shift that routine slightly earlier," Stothard says.
  • Go outside in the early morning to help adjust your internal clock. Morning light "ends the melatonin production" and "affects the way that your circadian system predicts your next sleep," she tells us.
  • Get good exercise to help tucker yourself out.
  • Aim to get 7+ hours of sleep a night.

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