Your Sleep Schedule Matters More Than You Think

Albert Einstein is popularly said to have slept around ten hours a night. LeBron James does something similar today. The basketball star, widely considered one of the greatest players in National Basketball Association (NBA) history, has said in interviews that he treats eight to nine hours a night as non-negotiable. His trainer has called sleep his number one recovery tool. 
For years the advice was simple. Get seven to nine hours of sleep and you are fine. That is not wrong exactly, but it is incomplete. The last few years of research have made that pretty clear.
Take a 2023 study out of the Multi-Ethnic Study of Atherosclerosis, published in the journal Sleep. It followed close to 1,800 adults for about seven years. People with stable sleep routines had a 39% lower risk of dying during that window than people whose sleep was erratic and short. That second group also tended to sleep less overall. So, this finding really speaks to the combination of consistency and enough rest, not regularity by itself.
For that isolated effect, look elsewhere. A 2023 study using UK Biobank data on nearly 89,000 people, published in the journal eLife, and a 2024 follow-up in the journal Sleep, found something sharper. How regular someone’s sleep timing was predicted their risk of death better than how long they slept did. That held even once duration was accounted for on its own. Meir Kryger, a professor emeritus of medicine at Yale, put it bluntly. Those who keep regular sleep schedules live longer than those who do not.
It helps to understand what is actually happening while you sleep, because the reason timing matters is not abstract. Sleep runs in cycles of roughly 90 minutes, four to six a night. Each cycle moves through stages. A light stage opens things up, just a few minutes, easy to wake from. Then a slightly deeper stage follows, where heart rate and temperature start dropping. This stage takes up the biggest share of the night. After that comes deep sleep, the body’s repair phase. It is hardest to wake from, and it is loaded into the first half of the night. Only afterward does rapid eye movement (REM) arrive, the stage tied to dreaming and memory. It starts short and lengthens with each cycle, until it dominates the back half of the night. Cut a night short, and REM is disproportionately what gets lost.
All of this runs on the circadian rhythm, the body’s internal clock. It is controlled by a small cluster of brain cells called the suprachiasmatic nucleus. This clock is not just deciding when you are tired. It is running hormone release, digestion, immune function and body temperature, all timed to light, darkness, and when you eat. When bedtimes and wake times keep sliding around, that clock falls out of sync with everything around it. Researchers call this circadian misalignment.
So, what is actually the best time to go to bed? A 2021 study published in European Heart Journal Digital Health tracked over 88,000 adults using wrist worn devices. People who fell asleep between 10 and 11 pm had the lowest risk of heart disease over roughly six years. That held even after adjusting for age, sex, smoking and other risk factors. But that is an average, not a rule everyone has to follow. Some of us are wired to be night owls, some early risers. Forcing a bedtime that fights your own biology usually just means lying awake, frustrated. What works better is figuring out when you naturally start feeling sleepy, building a schedule around that, and sticking to it, weekends included.
None of this requires a big life overhaul. Sleep clinicians point to the wake-up time, not the bedtime, as the anchor worth protecting first. The body adjusts to an earlier bedtime far more easily than it adjusts to an earlier wake time. Keeping your wake time within about thirty minutes, every day, is one of the more practical changes available. Getting outside or near bright light soon after waking helps lock that clock in place. Eating meals on a consistent schedule helps too, since digestion runs on the same internal clock as sleep does. And if you do have a rough night, the better move is waiting until you are actually tired the next night. Do not force an early bedtime. Just keep getting up at your normal time the next morning.
We cannot buy back a decade with a better mattress. We cannot out caffeine a clock that is out of sync. What we can do is start resetting it tonight, just by deciding what time we are getting up tomorrow, and doing the same thing again the day after. It might be one of the more honest ways we get to choose how long, and how well, we live.