Clocks fall back one hour this weekend, and that extra hour of sleep comes with a hidden catch for your body clock.
Quick Take
- Daylight saving time ends this weekend, giving most Americans an extra hour of sleep.
- Sleep specialist Dr. Shelby Harris told CBS Mornings the fall shift still disrupts the body’s internal clock.
- The American Academy of Sleep Medicine backs permanent standard time, citing it as closer to our natural biology.
- Simple fixes like morning sunlight, steady bedtimes, and lighter dinners can ease the adjustment.
The Clock Change Affects More Than Your Watch
Every November, clocks fall back and every March they spring forward. Most people treat it as a minor hassle. But sleep specialist Dr. Shelby Harris, a clinical professor at Albert Einstein College of Medicine, told CBS Mornings the shift does real work on your body. Your circadian rhythm, the internal clock that controls sleep and wake cycles, does not reset instantly just because your phone does.
Harris explained that even the “easier” fall transition can throw off sleep timing, energy levels, and mood for days. Parents of young children often see earlier wake-up times and more irritability right after the switch. Adults may feel off-kilter too, even while enjoying the extra hour in bed. The body does not simply trade an hour of darkness for an hour of light without some cost.
Why Sleep Doctors Prefer Standard Time Over Daylight Saving
The American Academy of Sleep Medicine has studied this question for years and reached a clear conclusion. The group’s 2020 position statement says permanent standard time “aligns best with human circadian biology,” matching the body’s internal clock better than daylight saving time does. The organization has pushed to end the twice-yearly switching altogether in favor of sticking with standard time year-round.
That stance carries weight because the spring transition, when clocks jump forward and people lose an hour, is linked to real danger. The academy’s statement points to increased risks of heart attacks, mood disorders, and car crashes right after that spring shift. The fall transition, by contrast, tends to be gentler on the body, since people gain sleep rather than lose it.
What the Evidence Actually Shows
A broader review of 157 studies across 36 countries adds useful nuance here. Researchers found that daylight saving transitions are not uniformly harmful across the board. Spring’s clock change was tied to more heart attacks and fatal traffic accidents, but researchers also found drops in certain violent crimes during daylight saving months. The fall transition showed a different pattern entirely, with some data pointing to lower all-cause mortality and fewer workplace injuries right after clocks fall back.
That distinction matters. Not every claim about clock changes carries the same scientific weight. Acute, short-term effects around the spring shift have solid research behind them. Long-term claims about living under one time system permanently are far less settled, and the sleep medicine academy itself acknowledges that chronic effects of year-round daylight saving time have not been well studied. Good reporting keeps those two categories separate instead of blending them into one scary headline.
Practical Steps to Beat the Post-Clock-Change Fog
Harris offered concrete, doable advice rather than vague warnings. Get natural light first thing in the morning to help reset your internal clock faster. Watch your caffeine intake, especially in the afternoon, since it lingers in your system longer than most people realize. Shift your bedtime gradually instead of forcing an abrupt change, and give your body a few days to catch up.
Meals matter too. Harris recommended avoiding large, fatty, or acidic meals within three hours of bedtime, since digestion can interfere with sleep quality. If hunger strikes late, a small snack combining carbohydrates and protein works better than a heavy dinner. None of this requires a special gadget or app. It just requires paying attention to habits most people already control.
Sources:
youtube.com, aasm.org, akleg.gov
