Your sleep schedule may matter as much as your hours, so start with your wake-up time

Key takeaways

• In a UK study of 60,977 adults who wore motion sensors for a week, everyone outside the least regular fifth had a 20% to 48% lower risk of dying over the next several years¹.
• A second team, analyzing more than 106,000 people from the same UK database, found a similar pattern, but no trial has yet tested whether steadier sleep helps people live longer².
• In a study of 61 college students, irregular sleepers slept about as many hours as regular ones, yet their body clocks ran about 2.6 hours later³⁴.
• A fixed wake time is a core instruction in stimulus control, part of the insomnia therapy the American Academy of Sleep Medicine strongly recommends⁵.
• The American Academy of Pediatrics has urged since 2014 that middle and high schools start at 8:30 a.m. or later, but Florida lawmakers repealed the state’s later-start mandate in 2025, news reports say⁶⁷.

Between 2013 and 2015, tens of thousands of middle-aged and older adults in the UK Biobank, a large British health study, wore a small motion sensor for a week¹². The devices logged when each person slept and woke. One analysis drew on more than 10 million hours of these recordings¹.

Researchers then followed 60,977 of those people for an average of about six years, and 1,859 died¹. The people whose sleep timing jumped around the most from day to day were the most likely to die¹. Their regularity predicted death better than how many hours they slept¹.

Most sleep advice counts hours. This research counted something else: whether you sleep and wake at about the same times. It doesn’t prove that a steady schedule adds years. But it lines up with advice that insomnia specialists, pediatricians and federal health officials have given for years, and a schedule costs nothing.

Below, we cover what the evidence shows, why your wake time matters most, and a two-week plan, with a simple score, for steadying your own sleep.

Scientists now score regularity, not just hours

In 2017, a team led by sleep researchers Andrew Phillips and Charles Czeisler introduced a measure called the Sleep Regularity Index, or SRI, in a study of college students³. It asks a simple question: how likely are you to be in the same state, asleep or awake, at a given moment and again 24 hours later²?

Higher scores mean steadier sleep². In the UK Biobank group, the middle score was 81¹.

Picture two people who each sleep 7 hours a night. One sleeps from 11 at night to 6 in the morning, every day. The other keeps those hours on weeknights but sleeps from 2 to 9 in the morning on weekends.

Their totals match. Their regularity doesn’t, because at 7 on a Saturday morning one is up and the other is asleep.

Researchers have computed the SRI from wearable sensors and from sleep diaries¹³. You can get a rough home version from a paper diary, using our own simple score later in this article.

Two big studies found the same pattern, but neither proves cause

The first study, published online in the journal Sleep in 2023 and in its January 2024 issue, split its 60,977 participants into five equal groups by regularity¹. Compared with the least regular fifth, the other four groups had a 20% to 48% lower risk of dying from any cause¹. Their risk of dying from cancer was 16% to 39% lower, and from heart and metabolic disease 22% to 57% lower¹.

The estimates took into account age, sex and ethnicity, plus social, lifestyle and health differences¹. Regularity still predicted death more strongly than sleep duration did¹.

A separate team, writing in the journal eLife in 2023, analyzed more than 106,000 UK Biobank participants over a median of about seven years². About 3,010 died². The least regular 5% had about a 53% higher risk of death than people in the middle, while the most regular 5% had about a 10% lower risk². Risk climbed most steeply at the irregular end².

Two independent analyses agreeing is meaningful. Still, both are observational, which means they watched people rather than changing anyone’s sleep. Four limits apply:

• The arrow may point backward. Illness, pain, depression or a new medicine can scramble sleep and also raise the risk of death. A week of sensor data can’t show which came first.
• Other factors travel with irregular sleep. Shift work, caregiving and money stress can upend sleep and harm health. Researchers adjust for what they can measure, not for everything.
• One week is a snapshot. It may not reflect a person’s usual life.
• No trial has tested it. In a commentary on the eLife study, Tianyi Huang noted that regularity hasn’t been tested in intervention studies, so whether improving it prevents disease remains an open question².

One finding is encouraging for ordinary people. The steepest risk sat at the chaotic end of the scale². The goal is staying out of the most irregular group.

Same hours, different body clock

The 2017 student study offers a clue to why regularity might matter. Phillips, Czeisler and colleagues followed 61 undergraduates who kept sleep diaries for 30 days³.

The most irregular sleepers got about as much sleep, on average, as the most regular ones⁴. But their melatonin, the hormone that rises in the evening as the body readies for sleep, started about 2.6 hours later³⁴.

Czeisler said that for these students, a 9 o’clock morning class fell at about 6 in the morning on their internal clocks⁴.

Steadier sleep went with better academic performance³. Irregular sleepers also got less daytime light and more light at night, and a computer model suggested those light patterns explained most of their delayed clocks³⁴.

The study was small, and it can’t show that irregular sleep caused poorer performance. But it shows how two people with the same hours can live on different internal schedules. Our article on circadian rhythms (topic 205) explains the body clock and “social jet lag,” and our upcoming article on morning light (topic 212) covers light timing.

In 2023, a National Sleep Foundation (NSF) panel chaired by Czeisler reviewed the research and concluded that people who keep steady bed and wake times tend to be more alert and to have better heart, metabolic and mental health⁸. The NSF is an advocacy group with industry partners: in 2010, for example, it lent a Serta mattress line the title “Official Mattress of the National Sleep Foundation”⁹.

Sleeping in on weekends: the experts don’t agree

The NSF panel said that when workday sleep falls short, 1 to 2 extra hours on days off can help most people recover⁸.

Others are more cautious. The American Academy of Pediatrics (AAP) says that teens who sleep in on weekends can make up part of the week’s shortfall but may worsen the disruption to their body clocks and their morning sleepiness at school⁶. A 2019 University of Colorado lab study found that weekend recovery sleep didn’t protect against the metabolic harm of short sleep; our article on sleep and metabolic health (topic 209) explains it¹⁰.

The Centers for Disease Control and Prevention (CDC) has taken the simplest line: everyone should go to bed and get up at the same times every day, weekends included¹¹.

A middle path fits all of this. If you’re short on sleep, add it at the front of the night by going to bed earlier, and keep your wake time close to your weekday time. That’s our suggestion, not a tested rule.

Your wake time is the anchor of insomnia treatment

When the American Academy of Sleep Medicine (AASM) issued its 2021 guideline on behavioral treatment for chronic insomnia, it strongly recommended cognitive behavioral therapy for insomnia, or CBT-I⁵. One of its core parts is stimulus control, and the guideline lists setting a consistent wake time among stimulus control’s goals⁵.

The instructions also say to go to bed only when you’re sleepy⁵. In other words, bedtime is allowed to float a little. Wake time is not.

There’s a practical logic to that. You can’t make yourself fall asleep, but you can decide when to get up. A fixed wake time is the one part of the night fully under your control. Our article on sleep pressure (topic 206) explains how this works with the body’s drive to sleep.

A schedule alone may not fix true insomnia. The AASM suggests that clinicians not rely on sleep hygiene tips by themselves for chronic insomnia⁵. If you’ve had trouble falling or staying asleep at least three nights a week for three months or more, that’s chronic insomnia, and it’s worth seeing a clinician¹². Our upcoming insomnia article (topic 235) covers CBT-I in depth.

Teens run on a later clock, and school bells haven’t caught up

In 2014, the AAP put the biology plainly⁶. Around puberty, the timing of sleep shifts later, by up to about 2 hours, and the average teen has trouble falling asleep before 11 p.m.⁶. Teens need 8.5 to 9.5 hours a night, the AAP said, and middle and high schools should aim to start no earlier than 8:30 a.m.⁶.

At the time, few schools met that mark. In a CDC analysis of the 2011–2012 school year, fewer than 1 in 5 public middle and high schools started at 8:30 or later, and the average start was 8:03 a.m.¹¹.

Do the math for a teen with a 6 a.m. alarm. Getting 8.5 to 9.5 hours means being asleep by about 8:30 to 9:30 p.m., hours before the average teen can easily fall asleep, according to the AAP⁶.

States have struggled with the trade-offs. A 2023 Florida law required high schools to start no earlier than 8:30 a.m. and middle schools no earlier than 8 a.m., with a 2026 deadline⁷. Districts warned of costs such as more buses and hard-to-hire drivers⁷.

In 2025, lawmakers rolled the mandate back. Under the new law, districts that keep earlier start times need only file a report with the state, a Gainesville TV station reported in July 2025⁷. Most Florida high schools start around 7:45 a.m.⁷.

At home, parents can help by keeping teens’ weekend wake times close to their school-day times, in line with the CDC’s call for a steady rise time every day¹¹. Our article on busy parents covers family routines.

Your two-week plan to anchor your wake time

For readers who value living in rhythm with nature, regularity may be the most natural sleep habit of all. It needs no product, no pill and no tracker, only a time you choose and keep.

The plan below is our own, built around the stimulus control instructions in the AASM guideline⁵.

When	What to do	Why
Day 1	Pick one wake time you can keep 7 days a week. Set one alarm and put it across the room	A consistent wake time is a stimulus control goal5
Day 1	Count back from that wake time by your sleep need (see topic 207) to find a target bedtime. Set a second alarm an hour before it to start winding down (see topic 213)	Gives sleep a predictable window
Every day	Get up at your anchor time, even after a bad night or a late evening	Protects the one part of the schedule you control5
Every night	Go to bed when you’re sleepy, but not long before your target bedtime	The guideline says bed only when sleepy5
Every day	Skip naps, or keep them short and early	Stimulus control advises against daytime napping5
Weekends	Wake within an hour of your anchor. If you’re short, go to bed earlier instead	The CDC advises a consistent rise time every day11
Days 7 and 14	Score your week, using the method below	Shows whether the plan is working

Our home regularity score

This is the library’s own simple method, made for this article. It is not the research SRI and hasn’t been validated.

1. Each morning, write down when you got up for the day and roughly when you fell asleep the night before.
2. For each day, give yourself 1 point if you got up within 30 minutes of your anchor time.
3. Give yourself 1 more point if you fell asleep within 30 minutes of your typical time that week (the middle value of your seven nights).
4. Add up the week. The top score is 14.

A score of 12 to 14 is steady. A score of 8 to 11 is mostly steady. At 7 or below, focus on the wake time first.

Picture someone with a 6:30 a.m. anchor who gets up on time Monday through Friday, at 8 on Saturday and at 9 on Sunday. If they fall asleep near their usual time on five nights, they score 5 plus 5, or 10. Getting up on time on just the weekend mornings would raise it to 12.

What the evidence shows

Claim	Evidence level	What it rests on
A regular schedule lowers your risk of early death	Promising but early	Two large UK sensor studies agree, but both are observational and untested in trials12
Regularity matters apart from total hours	Promising but early	Regularity outperformed duration; irregular students slept as long but had later clocks134
CBT-I, which includes a fixed wake time, helps chronic insomnia	Strong evidence	Strong AASM recommendation5
Stimulus control used alone helps insomnia	Promising but early	Conditional AASM recommendation5
Sleep hygiene tips alone treat chronic insomnia	Evidence says no, or unsafe	AASM suggests against it as a stand-alone treatment; it isn’t unsafe5
Sleeping in 1 to 2 hours on weekends repays lost sleep	Promising but early	NSF panel supports it; the AAP warns that it disrupts teens’ body clocks; a 2019 lab trial found no metabolic benefit6810
Teens’ body clocks shift later at puberty	Strong evidence	Summarized in the AAP’s 2014 policy statement6

When to see a clinician

A steady schedule helps healthy sleepers. It won’t fix a sleep disorder. See a clinician if:

• your snoring is loud and frequent, or you wake up gasping for air¹³;
• you often feel sleepy during the day, or doze off during routine tasks, especially driving¹³;
• you’ve had trouble falling or staying asleep 3 or more nights a week for 3 months or longer¹²;
• you feel creeping or tingling sensations in your legs that ease when you move or rub them¹⁴;
• you or a partner notice you kicking, punching or shouting as if acting out a dream¹⁵.

If you feel drowsy while driving, pull over somewhere safe. If sleepless nights come with hopelessness or thoughts of harming yourself, call or text 988. Our upcoming articles on sleep disorders (topics 235 to 241) go deeper.

Questions readers ask

The bottom line

Two large studies found that people with the most irregular sleep had higher death rates, and one found that regularity predicted risk better than hours did. Those studies can’t prove that a steady schedule protects you, but the habit is free, low-risk and backed by insomnia treatment guidelines.

Start with one change: a wake time you keep every day, weekends included. Let bedtime follow sleepiness, score your week, and see a clinician if sleep stays broken despite a steady schedule.

Related reading

• A few people truly thrive on six hours of sleep, but most of us don’t
• Sleep pressure builds all day, and your body clock decides when it wins
• One in seven workers clocks in during off-hours, and sleep is the first thing to anchor
• Your heart counts the weekly total while your habits count the repeats
• Busy parents need a few anchors more than a perfect routine

Sources

1. Windred DP, Burns AC, Lane JM, Saxena R, Rutter MK, Cain SW, Phillips AJK. “Sleep regularity is a stronger predictor of mortality risk than sleep duration: a prospective cohort study.” Sleep, 2024;47(1):zsad253 (abstract, UK Biobank). pubmed.ncbi.nlm.nih.gov
2. Huang T. “Another benefit of regular sleep” (Insight on Cribb L, et al., “Sleep regularity and mortality: a prospective analysis in the UK Biobank”). eLife, 2023;12:e94131. cdn.elifesciences.org
3. Phillips AJK, Clerx WM, O’Brien CS, Sano A, Barger LK, Picard RW, Lockley SW, Klerman EB, Czeisler CA. “Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing.” Scientific Reports, 2017;7 (DOAJ record). pubmed.ncbi.nlm.nih.gov
4. Sleep Review. News report on Phillips AJK, et al., irregular sleep patterns and academic performance in college students. June 20, 2017. sleepreviewmag.com
5. Edinger JD, Arnedt JT, Bertisch SM, et al. “Behavioral and psychological treatments for chronic insomnia disorder in adults: an American Academy of Sleep Medicine clinical practice guideline.” Journal of Clinical Sleep Medicine, 2021;17(2):255-262. pmc.ncbi.nlm.nih.gov
6. American Academy of Pediatrics, Adolescent Sleep Working Group, Committee on Adolescence, and Council on School Health. “School Start Times for Adolescents.” Pediatrics, 2014;134(3):642-649. drcraigcanapari.com
7. Butler C. “Florida schools no longer required to delay start times under new law.” WCJB, July 17, 2025, wcjb.com ; and Saunders J. (News Service of Florida). Jacksonville Today report on the Senate vote to repeal the start-time law, March 27, 2025, jaxtoday.org
8. National Sleep Foundation. “Consistent Sleep Schedules with New Consensus Guideline” (on Sletten TL, et al., Sleep Health, 2023). September 6, 2023. thensf.org
9. Sleep Review. “National Sleep Foundation and Serta Team Up to Promote Better Sleep.” May 12, 2010. sleepreviewmag.com
10. National Institutes of Health. “Weekend Catch-Up Can’t Counter Chronic Sleep Deprivation.” NIH Research Matters, March 12, 2019 (on Depner CM, et al., Current Biology, 2019). nih.gov
11. Centers for Disease Control and Prevention. “Most US middle and high schools start the school day too early.” Press release, August 6, 2015. archive.cdc.gov
12. National Heart, Lung, and Blood Institute. “Insomnia: Diagnosis.” NIH, updated March 24, 2022. nhlbi.nih.gov
13. National Heart, Lung, and Blood Institute. “Sleep Deprivation and Deficiency: Diagnosis.” NIH, updated July 30, 2026. nhlbi.nih.gov
14. MedlinePlus. “Sleep Disorders.” National Library of Medicine, updated December 4, 2025. medlineplus.gov
15. American Academy of Sleep Medicine. “REM Sleep Behavior Disorder.” Sleep Education, 2021 (reviewed by Andrea Matsumura, MD). sleepeducation.org