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This is the longevity focused metric in your sleep score that can indicate how well you’re ageing — experts explain why and how to improve yours
What if I told you there's a way to boost your longevity that doesn't involve red light, cold plunges, or quaffing superfoods? In fact, it's something we can all do for free: keep a regular sleep schedule.
My sleep tracker is always urging me to get to bed on time and, judging by two major new studies published this year showing that sleep regularity is a crucial aspect of ageing better, it's clear that my sleep tracker is looking out for my long-term health.
Key take-aways: At a glance
- The 'master switch' for longevity: Sleep regularity is the ultimate predictor because it sets the schedule for your entire body. It's what controls the timing of the cellular repair that keeps your organs young.
- The one-hour sleep rule: Science now indicates that staying within a 30-minute window of your target bedtime and wake time every day is vital for longevity. Being consistent with this 'one-hour' window is the gold standard for a healthy circadian rhythm.
- The 4-year longevity boost: A huge new study by Vitality and The London School of Economics and Political Science (LSE) found that consistent sleep timings paired with getting 7+ hours of sleep a night can help increase your life span by up to four years. This is known as the 7:1 Sleep Rule.
- The weekend lie-in trap: Scientists now believe that 'social jetlag'—shifting your sleep schedule on the weekends—accelerates biological aging and decline.
- The 'Regularity' metric: Most high quality sleep trackers, including the Apple Watch, Oura Ring, and Garmin Index Monitor, track 'sleep consistency' to help you monitor this vital longevity marker.
- Optimizing your bedroom for sleep: Experts recommend using temperature-controlled bedding and smart lighting to anchor your circadian rhythm and help you stick to a regular sleep schedule.
What is sleep regularity?
Sleep consistency is all about going to bed and waking up at roughly the same time every day to regulate your circadian rhythm (and therefore your sleep/wake hormones).
Instead of simply focusing on how many hours you sleep, researchers now use the Sleep Regularity Index (SRI). According to the doctor-cited science health journal Nature, the SRI is used to "measure an individual’s sleep/wake consistency over time."
According to a paper by the researchers who created the SRI, 'the index is scaled so that an individual who sleeps and wakes at exactly the same times each day scores 100, whereas an individual who sleeps and wakes at random scores 0.'
"Higher sleep regularity scores are associated with better metabolic health, improved cardiovascular markers, and lower mortality risk," explains Dr. Ro.
When you have an irregular sleep schedule, you’re essentially putting your body in a state of stress, he says. This can fast-track you toward type 2 diabetes, obesity, and cognitive decline.
The social jetlag trap
Social jet lag (when your work or social habits get in the way of your sleep patterns) is the most common interference in sleep consistency.
People's sleep schedules tend to shift significantly between weekdays and weekends — I must admit, I'm guilty of this.
Dr. Ro says a common example is waking at 6am during the workweek and then sleeping until 9am or 10am on the weekend.
"Even though the person has not traveled, the body experiences a shift similar to crossing time zones. Repeating that cycle week after week can disrupt hormone rhythms, metabolism, and sleep quality,” he explains.
Why sleep regularity is the master switch for longevity
While CDC guidelines still recommend that adults get 7 or more hours' sleep a night, new research shows that sleep regularity is actually a stronger predictor of mortality risk compared to how much sleep you're getting, and combining that regularity with enough sleep can add up to four years to your life.
A 2024 Windred et al study of more than 60,000 participants found that sleepers with higher SRI scores had a 20% to 48% lower risk of all-cause mortality than those with low scores, and was a stronger predictor of all-cause mortality than sleep duration.
Additionally, the Vitality and LSE study of more than 47 million nights of sleep data, published in January 2026, concluded that getting seven hours of sleep per night, while maintaining a consistent bedtime within a one-hour window, can lead to 24% lower mortality risk when compared to people who don't do either.
In terms of lifespan, they translated that to up to potentially four more years of life.
Miller, who is on a journey to reach 130 years old, explains: "Consistent sleep allows your body to predict when to repair tissue and flush toxins.
"When our circadian pattern is disrupted too often, we pay the short-term price (inflammation, brain fog, lack of energy) and the price long-term (early death and a great chance of diseases).
“Quality is a byproduct of consistency," he adds. "If you want to live longer, stop chasing the amount of sleep and start mastering the timing of it."
So below, we'll cover habits that can improve your sleep regularity, and look into how the best sleep trackers can help you ace that consistent sleep schedule...
How to find your sleep consistency score
As I mentioned earlier, my sleep tracker, an Oura Ring, doesn't let me get off lightly when I have a late night. It sends me notifications reminding me I should be asleep and deducts points from my sleep score if I sleep at irregular times, even if I clock eight hours.
That's why a reliable sleep tracker is such a handy tool for maintaining that all-important, and potentially life-extending sleep schedule. All the best trackers measure sleep regularity and take consistency into account when calculating your nightly sleep score.
“Sleep tracking can be useful because it turns something invisible into measurable data," emphasises Dr. Ro. "Wearable trackers can highlight patterns such as bedtime variability and sleep timing drift. When people see those patterns clearly, it often motivates them to create more consistent sleep habits.”
Here's how to find your sleep consistency metric on popular health trackers:
Oura Ring
Oura measures sleep consistency by tracking the regularity of your bedtime and wake-up times. You'll find a dedicated sleep timing measurement in your sleep report.
After 90 days of constant wear, Oura learns your natural chronotype and will align your sleep timing with this data under the 'Body Clock' tab.
Apple Watch
Your bedtime is one of three key metrics that go into calculating your Apple sleep score. In the sleep section of the Apple Health app, you can view how close your bedtime was to your average.
Whoop
The fitness and performance focused Whoop band delivers a 'sleep consistency' percentage under the sleep tab. This percentage reflects how similar your bed and wake times are over a rolling four-day period.
Garmin
Although there isn't a dedicated sleep consistency measurement in the Garmin sleep report, you can view your detailed breakdown of sleep times and stages to manually cross-check your consistency.
How to improve your sleep consistency score
So, you know sleep regularity enhances your chances of living a longer, healthier life, and you know where to find the metric on your sleep tracker of choice. But what can you do, starting tonight, to improve your sleep consistency?
Strap in, I've got the tips and tactics from the experts...
The 7:1 Rule
Of course, it's nigh-on-impossible to fall asleep at the exact same minute every night, so experts recommend a one hour window around sleep and wake times.
Obtaining 7 hours of sleep per night within a 1-hour window is one of the key sleep behaviours recommended by Vitality researchers for extended life expectancy. Dr. Ro also highlights that avoiding large timing swings helps maintain circadian stability.
This one hour window takes the pressure off falling asleep as soon as you get into bed. Instead of panicking about getting to sleep right on time, prioritise maintaining a calming nighttime routine. Once this routine is established, your body should get used to winding down at roughly the same time each night.
Anchor your morning
Dr. Ro says locking in a stable wake time, and exposing yourself to sunlight soon after waking, is the best starting point for avoiding sleep deprivation and getting better sleep.
“Natural light exposure within the first thirty minutes after waking helps reinforce the body’s internal clock,” he explains. Essentially, the sunlight tells you brain it's time to be alert.
Light, along with waking at roughly the same time each day, signals the brain when to release cortisol in the morning and when melatonin should rise later that evening. "Once that rhythm stabilizes, the body naturally begins to develop sleep pressure at a predictable time at night," says the Texas-based physician.
That means you fall asleep fast and reap the health benefits of a consistent sleep schedule. It's a double win.
Don't over-correct
Now, I had a pressing question for the experts: There are people who cannot perfectly control their sleep schedule (new parents and shift workers, I'm thinking of you), so what is the most important anchor for them: bedtime or wake time?
"The biggest anchor is a consistent wake-up time," confirms Miller, and you should "protect this at all costs." Experts now agree it's better to wake up at your usual time, even if you have a late night, and take a 20-minute nap later than to "sleep in" and shift your rhythm.
The founder of Eternum Longevity Center advises: "Try to schedule 7 to 9 hours in bed if possible, but wake up at the same time every day, even weekends, regardless of bedtime."
Admittedly, skipping a couple of hours sleep one night isn't great, but throwing off your circadian rhythm for the following few nights can lead to accumulating a bigger sleep debt.
The best tech to help you maintain regular sleep times
As tech gurus here at Tom's Guide, we're always keen to wax lyrical about gadgets that improve our sleep routines.
Focussing on the fact light and temperature are two of the biggest factors that influence sleep, here are our tried-and-tested products — all of which can help you get to bed, or get up, on time...
A SMART BED: With features like temperature monitoring to enhance your sleep quality, smart beds like the Eight Sleep Pod, can help you drift off and wake up at consistent times. "I’m a massive advocate for bed coolers like the Eight Sleep Pod 5. Being able to thermally regulate your environment is a game-changer," says Miller.
SMART LIGHTING: If you're looking to upgrade your home for better sleep, Philips Hue lights are a great place to start. With built-in sunset features, these lights can be programmed via the accompanying app to dim in the evening. Being in a darker room can to help promote melatonin release and aid you in feeling sleepy on time.
A SUNRISE ALARM CLOCK: Come morning, the best sunrise alarm clocks, like the Hatch Restore 3 or Lumie Bodyclock Shine 300, can help you hone a consistent wake up time. Gradually getting brighter over a set period of time, they are particularly effective on dark mornings as they simulate a sunrise and help you wake more naturally compared to a blaring alarm.
SMART BLINDS: And when the mornings naturally get brighter, smart blinds are a great home improvement. Typically controlled via apps or home smart assistants, you can set them to let in light at the same time every morning.
