By Dr. K. Nicole Mims, board-certified sleep physician
First and foremost, I’m firmly in the Save Standard Time camp, and here's why.
Same sun, different clock
To explain why, let's look at the sunrise in Huntsville on the shortest day of the year. Sunrise, sunset, and a 6:30 alarm. Under standard time, the sun comes up at 6:50 in the morning. Under permanent daylight saving time, it comes up at 7:50. Same sun. Same city. Different clock. Under permanent daylight time, your alarm goes off a full hour before sunrise, so we wake up in the dark.
Under standard time, your 6:30 alarm beats the sun on 83 out of 128 mornings. Roughly two thirds. Under permanent daylight time, it beats the sun on all 128. Every single one. And the latest sunrise slips all the way to 7:54 in the morning. That's not a small difference. That's an entire season of waking up in the dark.
Why the light matters so much
Let me back up for a minute and explain why the light matters so much.
Every cell in your body runs on a clock. It's called your circadian rhythm, and it's roughly a 24-hour cycle that tells your body when to be awake and when to be asleep. And the single most powerful thing that sets that clock is sunlight. Not your alarm, not your coffee, not your willpower. Light, hitting your retina, in the morning. That morning light does something specific: it stops melatonin, the hormone that makes you sleepy, and it tells your brain, this is the start of the day. Which is why sleep doctors like me encourage morning sunlight in a daily routine. Get outside within an hour of waking up. Yes, with sun protection. The point isn't a tan, it's the timing signal. The sun tells your cells when to be awake and when to be asleep.
When circadian rhythms break down
So when that rhythm gets out of sync, it doesn't just make you tired. It shows up all over your body.
Your mood. Your gut. Your heart. And this is where the research gets really interesting. We used to think of ADHD and depression as purely brain chemistry problems. What's emerging is that disrupted circadian rhythms are woven into both of them. In ADHD, melatonin onset is delayed by roughly 45 minutes in children and about 90 minutes in adults. And when researchers advanced that timing, ADHD symptoms improved. In depression, circadian misalignment is so tied to symptoms that shifting the body clock is being studied as a treatment approach itself. So this isn't a soft lecture about sleep hygiene. Your body clock is load bearing.
What a clock change actually does
Here's the frustrating part. As much as I'd like to see us stop changing the clocks, we're not there yet, so in the meantime we deal with time changes.
The good news is, falling back is the gentler direction. We gain an hour instead of losing one, and most of the scary data about time changes is about springing forward. But the acute time change still affects us. A nationwide study out of Finland looked at ten years of ischemic strokes. In the first two days after a clock change, stroke hospitalizations rose about 8 percent. On that Monday, 9 percent. In people over 65, it was closer to 20 percent. It shows up on the job too. A study of U.S. mining injury records going back to the eighties found 5.7 percent more injuries on the Monday after we spring forward, and far more workdays lost. Those workers had slept about 40 minutes less the night before. And it shows up on the road. The largest US study of fatal crashes found a 6 percent increase in the workweek after the spring clock change. A newer controlled analysis, using states that don't change their clocks as a comparison, found morning fatal crashes up nearly 26 percent in the days after springing forward.
And underneath all of it, you just sleep less. In a UK Biobank study of nearly 12,000 people wearing sleep trackers, sleep on the Sunday of the spring change was 65 minutes shorter than the Sunday before. Falling back runs the other way — about 33 minutes longer. But even with falling back, your body doesn't get the memo that the clock moved. Your circadian rhythm takes days to shift, and in the meantime your whole schedule just moved an hour earlier — school, work, dinner, bedtime.
How to handle falling back
So here's what I actually recommend for this weekend.
- Get outside early. Within an hour of waking, get your face in the sun. Ten to twenty minutes is plenty. Overcast still counts. This is the single highest-leverage thing on this list.
- Set your clocks Saturday night and go to bed at your normal bedtime, or at least stay within 30 minutes of your body's bedtime clock.
Most people are settled within a few days. If you're still wrecked two weeks out, that's not the time change anymore — that's worth a conversation.
If trouble sleeping has become a pattern, I see patients in Alabama and North Carolina by telehealth. You can book a visit here.
References
- American Academy of Sleep Medicine. Fall-back adjustment guidance. https://sleepeducation.org
- American Academy of Sleep Medicine / Coalition for Permanent Standard Time. Position on permanent standard time.
- Sipilä JOT, Ruuskanen JO, Rautava P, Kytö V. Changes in ischemic stroke occurrence following daylight saving time transitions. Sleep Medicine. 2016;27-28:20-24. doi:10.1016/j.sleep.2016.10.009
- Fritz J, VoPham T, Wright KP Jr, Vetter C. A chronobiological evaluation of the acute effects of daylight saving time on traffic accident risk. Current Biology. 2020;30(4):729-735. doi:10.1016/j.cub.2019.12.045
- Lange MG, et al. The effects of daylight saving time clock changes on accelerometer-measured sleep duration in the UK Biobank. Journal of Sleep Research. 2025. doi:10.1111/jsr.14335
- Barnes CM, Wagner DT. Changing to daylight saving time cuts into sleep and increases workplace injuries. Journal of Applied Psychology. 2009;94(5):1305-1317. doi:10.1037/a0015320
- Does daylight saving time increase traffic crashes? Seasonal confounding and a morning fatality effect. PubMed ID 42673743. https://pubmed.ncbi.nlm.nih.gov/42673743/
- ADHD as a circadian rhythm disorder: evidence and implications for chronotherapy. Frontiers in Psychiatry. 2025. doi:10.3389/fpsyt.2025.1697900
- Circadian disruption and human health. JCI. 2021.