By Paul Muchowski, Ph.D. — Founder & CEO, Defined Sleep

I've spent a lot of time pondering what happens inside the brain during sleep — the molecular choreography of deep sleep clearing metabolic waste, the precise architecture of REM cycles and synaptic cooldown that help to consolidate memory. So every March, when 300 million Americans involuntarily agree to scramble their circadian rhythms in unison, I experience something between professional horror and genuine amusement.

Think about it. If a pharmaceutical company proposed a nationwide intervention that increased heart attacks by 24% the following Monday, spiked traffic fatalities, cost an estimated $411 billion annually in lost productivity and healthcare expenses, and didn't even achieve its original purpose of saving energy — the FDA would shut it down before the ink dried on the application. But because we cutely call it "Daylight Saving Time (DST)" and it arrives with the pleasant promise of longer evenings, we set our alarms, wake up groggily to change all of the clocks in the house, grumble for a week, and move on.

We shouldn't move on so quickly. Here's why — and what you can actually do about it.

 

What One Hour Really Does to Your Brain

Most coverage of DST focuses on the obvious: you lose an hour of sleep, you're dragging on Monday, but you eventually adjust. That framing dramatically undersells what's happening.

Your circadian rhythm isn't a preference. It's a 24-hour biological clock governed by light exposure, melatonin secretion, and core body temperature fluctuations that have been calibrated by hundreds of thousands of years of evolution. When you shift that clock by even one hour, you don't just lose 60 minutes of sleep — you disrupt the timing of every sleep stage.

Deep sleep (slow wave sleep) and REM sleep don't distribute evenly across the night. Deep sleep concentrates in the first half; REM dominates the second. When your alarm fires an hour earlier than your brain expects, it preferentially cuts into your final REM cycle — the one responsible for emotional regulation, memory consolidation, and creative problem-solving. This is why the Monday after "spring forward" doesn't just feel tiring, it feels off. Your mood is thinner. Your patience is shorter. Your ability to synthesize complex information is measurably degraded.

A 2025 study published in the Proceedings of the National Academy of Sciences by Stanford Medicine researchers found that the biannual clock switch is, from a circadian health perspective, the worst of all possible options. Their county-by-county modeling estimated that permanent standard time alone could prevent roughly 300,000 cases of stroke per year and reduce obesity prevalence by 2.6 million people. Permanent daylight saving time would capture about two-thirds of that benefit. Switching back and forth? That's what we chose. It's the circadian equivalent of ordering the sampler platter of bad options.

 

The Part Nobody Talks About: It's Not Just One Night

Here's the thing that frustrates me as a sleep researcher: the disruption doesn't resolve on Tuesday. Studies using actigraphy — wrist-worn devices that track actual sleep patterns — show that most people don't fully re-synchronize their circadian clocks for five to seven days after the spring transition. Some individuals, particularly those with existing sleep difficulties, take even longer.

For the 70 million American adults who already struggle with sleep, DST isn't a one-night inconvenience. It's a week-long amplification of a problem they deal with every single night. And for the 42 million women aged 40–55 navigating perimenopause — a population where 56% already report sleeping fewer than seven hours per night — the timing couldn't be worse. Spring DST typically lands right when seasonal hormone fluctuations are already making sleep regulation harder.

 

Five Things That Actually Help (From Someone Who Studies This)

I'm not going to tell you to "just go to bed earlier." If that worked, the sleep supplement market wouldn't be a multi-billion dollar industry. Here's what the circadian science actually supports:

1. Shift in 15-minute increments, starting now. Four days before March 8, move your bedtime and wake time earlier by 15 minutes each day. By Sunday, your body has already absorbed the full hour. This sounds simple, and it is simple. It also works better than anything else on this list, and almost nobody realizes this easy hack.

2. Front-load your light exposure. Your circadian clock is most sensitive to light in the first two hours after waking. Get outside within 30 minutes of your alarm — even 10 minutes of overcast morning light delivers enough lux to advance your internal clock. This is the single most powerful circadian reset tool available, and it's free.

3. Blackout your evenings. The flip side of morning light is evening darkness. After 8 PM in the days surrounding the transition, dim your screens, lower your house lights, and give your brain the signal that nighttime is approaching. Melatonin onset is suppressed by even moderate evening light exposure — and your phone qualifies as moderate.

4. Protect your deep sleep window. The first 90 minutes of sleep is where the majority of your deep sleep occurs. Alcohol, late meals, and elevated room temperature all selectively suppress deep sleep. In the week around DST, be especially disciplined about keeping your bedroom cool (65–68°F), finishing your last meal three hours before bed, and skipping that second glass of wine.

5. Support your sleep architecture, not just your sleep duration. This is where I'll make the obvious disclosure: I created Defined Sleep specifically because I couldn't find any sleep supplement that actually addressed sleep quality — the deep and REM stages that contribute to restorative sleep — unlike the vast majority of sleep supplements which simply sedate and knock you unconscious. Our clinical trial, published in the Journal of Clinical Sleep Medicine, demonstrated up to a 2x increase in deep and REM sleep with no next-day grogginess, no sedation, and no reported side effects. During a circadian disruption like DST, supporting the architecture of your sleep matters more than simply adding minutes.

 

The Bigger Picture

The American Academy of Sleep Medicine, the American Medical Association, the National Sleep Foundation, and the Society for Research on Biological Rhythms have all called for the elimination of biannual clock changes in favor of permanent standard time. The science is about as settled as sleep science gets. The only thing standing in the way is congressional inertia — which, come to think of it, might itself be a symptom of chronic sleep deprivation, lol.

But until rational science based policy catches up with biology, the best thing you can do is take your own circadian health seriously. Not just during DST week, but every night. The data are clear: deep and REM sleep aren't luxuries. They're when your brain clears toxins, consolidates what you learned, and repairs the wear of the day. Losing even one cycle has measurable consequences.

So this March 8, when your alarm goes off and your body insists it's still the middle of the night — it is. Your hypothalamus isn't wrong. The clock on your wall is.

Plan accordingly.

 

FAQs

1. Why do people stay up late one night a year?

People stay up late for celebrations, traditions, and social connection. Events like New Year’s Eve create a shared moment where sleep feels less important than the experience.

2. Is losing one night of sleep bad for you?

One night of reduced sleep isn’t harmful for most healthy adults. The issue arises when poor sleep becomes a regular habit.

3. How can I recover after a late night?

Hydrate, get sunlight in the morning, take a short nap (20–30 minutes), and return to your normal sleep schedule the next night.

4. Why does staying up late feel exciting?

Late nights break routine and often involve socializing, music, and celebration, which trigger dopamine and make us feel energized.

5. How can I enjoy the night without feeling tired the next day?

Take a short nap beforehand, avoid too much caffeine or alcohol, and plan a calm next day so your body can recover.

6. Does one late night ruin your sleep cycle?

Not permanently. Your body can reset quickly if you go back to your regular sleep schedule right away.

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Paul Muchowski, Ph.D. is the founder and CEO/CSO of Defined Sleep. A former UCSF Professor with 60+ published studies, he created the first clinically-validated CBD sleep supplement, published in the Journal of Clinical Sleep Medicine (ClinicalTrials.gov ID: NCT05233761). Learn more at definedsleep.com.