夏令时 冬令时 时钟调整 | daylight saving time clock change
Daylight Saving Time & Sleep
A one-hour clock change is a mini jet lag. Shift your bedtime 15 minutes a day for 4 days and glide through the switch — here's your plan.
Which change is coming?
Why one hour knocks people out
Your internal clock doesn't reset when the wall clock does — it drifts by roughly 15–30 minutes per day. That makes the DST switch a small jet lag, and the spring forward version is the harder one because you lose an hour and mornings turn dark again. The effects are measurable: studies have found a short-term bump in traffic accidents, workplace injuries, and hospital admissions for heart rhythm problems in the days after the spring transition (Janszky 2008, N Engl J Med correspondence). The fix is cheap: pre-shift your schedule in 15-minute steps so the change never exceeds what your body can absorb in one day.
📖 Related reading: How Your Circadian Rhythm Works · Sleep Hygiene: 14 Rules · Best Time to Sleep
Frequently asked questions
Does a one-hour change really affect sleep?
Yes — your body clock shifts only 15–30 minutes per day, so a full hour takes several days to absorb. Sleepiness and accident statistics spike in the first week after the spring forward change.
What about children and pets?
They don't read calendars. Shift their feeding and activity schedule by 15 minutes a day alongside yours — most kids and dogs adjust within 3–4 days using the same plan.
Should I use the extra hour in fall to sleep in?
Keeping your normal wake time (in new clock terms) protects your rhythm better than sleeping in. If you pre-shifted your bedtime, you simply wake up naturally at the same clock time as before — no debt, no grogginess.
Do all places change clocks?
No. Most of the US, Canada and Europe observe DST; most of Asia, Africa and regions near the equator don't. Arizona (except the Navajo Nation), Hawaii and Puerto Rico stay on standard time year-round.
Disclaimer: This tool is for general informational purposes only and is not medical advice. If you have chronic sleep problems, please consult a healthcare professional.