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National Sleep Foundation’s 2021 Sleep in America® Poll Shows Gaps Between Public Sentiment and the Effects of Clock Change

Contact: Stephanie Corkett


National Sleep Foundation’s 2021 Sleep in America® Poll Shows Gaps Between Public Sentiment and the Effects of Clock Change

Washington, D.C. (March 14, 2021) – Most Americans don’t think their sleep, routines, or moods are affected by changing the clocks. In the National Sleep Foundation’s national, random-sample survey, over 70 percent of those in Daylight Saving Time-observing states said time changes in either direction aren’t a problem for them.

“We’re seeing gaps between what the public thinks and both published research and real-world observations of the clock change’s effects on health. Evidence has shown that changing the clock twice a year is detrimental to our circadian rhythm and overall health and safety, including cardiovascular events, mental health issues, and even traffic fatalities,” said Dr. Rick Bogan, Board Chair of the National Sleep Foundation.

Just one in four respondents would stick with the current system of two clock changes during the calendar year. Slightly more than half, fifty-four percent, of Poll respondents said they preferred year-round Daylight Saving Time, the “spring ahead” clock setting where time is moved forward by one hour.

“It’s understandable why Daylight Saving Time is appealing, but it doesn’t fit our body clocks like Standard Time. This is an opportunity for us to continue educating the public on the role and importance of the science behind our sleep,” added Bogan.

Switching to permanent Standard Time would better align our bodies to daily sunrise and sunset which influences the natural sleep/wake cycles, also called circadian rhythm. Your body and brain work together in multiple ways to create and regulate this process, and sleep can suffer when your body’s circadian rhythm is out of sync. Most adults need between seven and nine hours of sleep, followed by 15 to 17 hours of being awake.

For those who are affected by the changing of the clock, the National Sleep Foundation recommends gradually altering your bedtime and wake time by shifting the times forward 10-15 minutes a day for one week leading up to the clock change. You can also help your body adjust by altering your light exposure. Exposing yourself to bright light upon awakening and dimming the lights in the evening, while limiting electronics use, can help with falling asleep earlier.

For more information about circadian rhythm and other sleep health topics, visit


About the National Sleep Foundation

The National Sleep Foundation (NSF) is a 501(c)3 nonprofit corporation dedicated to improving health and well-being through sleep education and advocacy. Founded in 1990, the NSF is committed to advancing excellence in sleep health theory, research and practice. 


About the Sleep in America® Poll

The Sleep in America Poll is the National Sleep Foundation’s premier annual review of current sleep topics. The Poll was first conducted in 1991 and has been produced since 2018 by Langer Research Associates. The full Sleep in America Poll findings, including methodology, can be found at