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Seasonal Time Changes and Performance

Does “springing ahead” disrupt performance?

Graphic showing seasonal time changes

A lot of people dread the seasonal time changes, and there’s a lot of debate about the consequences of the practice. If you’ve ever noticed a change in your client’s performance around the spring time change, you may be on to something. Research provides insight into a potential adverse effect on running performance due to the “spring forward” adjustment. According to a study published in Chronobiology International, marathon runners perform worse in springtime races held on the transition day to daylight saving time (2021; 39 [1], 151–57).

Using a database that covered 18 years (2000–2018), University of Georgia researchers evaluated average run times for all finishers in marathon runs on the spring and fall daylight saving time transition days. They also compared runs on the same courses that occurred on days with no time transition. Average running time was worse by about 12 minutes on the spring daylight saving time day, but unaffected during the autumn transition.

“However, I speculate that slowed run time in the spring is either due to sleep loss or the shift in the timing of the race in relation to the runners’ internal biological clock—our bodies work best when our body clock is in synchrony with the environmental time, and on shift days this timing is disrupted for a day or so,” said study author Patrick O’Connor, PhD, professor of kinesiology, University of Georgia.

The American Academy of Sleep Medicine recommends eliminating seasonal time changes and adopting year-round standard time, “which aligns best with human circadian biology and provides distinct benefits for public health and safety.”

See also: Best Time for Swimming Performance

Shirley Archer, JD, MA

Shirley Archer, JD, MA, is an internationally acknowledged integrative health and mindfulness specialist, best-selling author of 16 fitness and wellness books translated into multiple languages and sold worldwide, award-winning health journalist, contributing editor to Fitness Journal, media spokesperson, and IDEA's 2008 Fitness Instructor of the Year. She's a 25-year industry veteran and former health and fitness educator at the Stanford Prevention Research Center, who has served on multiple industry committees and co-authored trade books and manuals for ACE, ACSM and YMCA of the USA. She has appeared on TV worldwide and was a featured trainer on America's Next Top Model.

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