Sleep debt: can you catch up on lost sleep?

Five nights of six hours, then a big Saturday sleep-in. It feels like you've paid the week back. Have you?

The short answer: partly. Extra sleep on your days off can help you recover from a busy week, but one long lie-in rarely clears the whole debt, and a very late wake-up can make Monday harder. The steadier way to catch up is a little more sleep, spread over several nights, with your wake time kept close to normal.

Over the weekend, posts about running on empty trended online, as people shared weeks of short nights and the pull of an early bedtime. If that sounds like your week, here is what sleep debt is, what actually helps, and how your own nights look on the Thrive Health Band.

What is sleep debt?

Sleep debt is the gap between the sleep your body needs and the sleep you actually get, added up over several nights. Most adults need 7 to 9 hours a night, according to the Sleep Health Foundation, and Australia's 24-hour movement guidelines for adults recommend 7 to 9 hours of good quality sleep with consistent bed and wake-up times.

Say you need eight hours but sleep six for five nights. That's roughly ten hours short by Friday. You may not feel all of it at once. It tends to show up as heavier mornings, a stronger afternoon slump, a shorter fuse and more cravings for coffee and snacks.

Can you catch up on sleep at the weekend?

Partly, yes. A US expert panel from the National Sleep Foundation reviewed the research and concluded that when weekday sleep is short, sleeping an extra one to two hours on non-work days can help most adults recover. The same US expert panel also found that regular sleep timing matters for health, and its full consensus statement notes that catch-up sleep may not fully make up for what was lost, and that it can take several days to recover from even one hour of lost sleep.

There's a catch with big sleep-ins, too. Waking at 11am instead of 6:30am shifts your body clock later, a bit like flying west for the weekend. That's the idea behind social jetlag and Monday tiredness. So a sleep-in can help, but a modest one works better than a marathon one.

Do naps help pay back sleep debt?

A short nap can take the edge off. The Sleep Health Foundation says 15 to 30 minutes is best, and that a nap can help you feel more awake and focused. It also says a nap can't replace good quality sleep at night, and that long or late naps can make it harder to fall asleep at your usual time. Early afternoon, around 2 to 3pm, is often the easiest time to nap. Our article on always feeling tired, naps and nights has more.

How to catch up on lost sleep, without wrecking next week

Add sleep at the start of the night. Going to bed 30 to 45 minutes earlier for a week is gentler on your body clock than sleeping until lunchtime.
Keep your wake time within about an hour. On your days off, let yourself sleep a little longer, but try to be up within an hour or so of your usual time.
Get morning light. Light soon after waking helps keep your body clock in time. Here is more on the morning sunlight walk.
Nap short and early. Keep naps to 15 to 30 minutes and before mid-afternoon.
Go easy on late coffee and alcohol. Both can make the sleep you do get less restful. See how long caffeine lasts and how alcohol affects sleep.
Protect the basics. A cool, dark room and a wind-down without screens make it easier to use the time you've set aside. The sleep hygiene basics cover the rest.

If you're wondering whether you can ever sleep too much, our piece on oversleeping looks at that side of the question.

How Thrive shows a run of short nights

Sleep debt builds up over days, so it helps to see the whole week, not just last night. The Band has no screen, so you can wear it day and night, and the Thrive by Optihealth app brings your nights and days together.

Sleep, four ways. Thrive shows Quality, Quantity, Regularity and Timing, plus hours slept each night, so a week of short nights, or a weekend that drifts late, is easy to spot.
Naps counted separately. Naps show up as their own sessions under your overnight sleep.
Tonight's focus. Each day the app suggests a few simple actions for tonight, based on your recent sleep.
Recovery sleep extension. A seven-day experiment asks you to add 30 to 45 minutes to your sleep window and keep your wake time steady, then shows what changed in your sleep and energy.
Recovery Estimate. Thrive combines last night's sleep, your activity and your overnight heart rate to show whether you're ready for another full day or still catching up.
Bedtime Reminder. Set a reminder in the app, from your sleep pattern or a time you choose.
Ask Thrive. Try "Have I been sleeping less this week?" or "Did my Saturday sleep-in help?"

Thrive doesn't give you a single sleep debt number. Instead, it learns what is usual for you right across your health, from sleep and heart to stress and mood, temperature, nutrition and more, and your Health Fingerprint is ready after about 30 days of wear.

When to talk to your GP

Feeling flat after a short week is normal. But if you're often sleepy during the day even when you give yourself enough time in bed, you nod off when driving, a bed partner notices loud snoring or pauses in your breathing, or you've felt low or anxious for a while, talk to your GP. Thrive isn't a diagnosis, but you can show your Thrive trends to your GP, and Ask Thrive can help you line up a few weeks of sleep and energy first. Here is how to use Ask Thrive before a GP appointment.

Before you buy

Thrive Health Band: A$589 for the band including 12 months of the Thrive plan, paid upfront. Prices are in AUD and include GST.

Free shipping. Your 12 months start when you activate your Band, and there's no automatic renewal.

At renewal: a new band plus 12 more months for A$589.

Or keep your band and renew the plan for A$240 a year.

Or A$29 a month with no lock-in.

One size, IP68, up to 14 days battery, 12-month warranty, not a medical device, no Apple Health sync. The app is Thrive by Optihealth on iPhone and Android.

See today's price on the Thrive store

Consumer guarantees under Australian Consumer Law always apply. See Returns if something is wrong with your purchase.

Common questions

How long does it take to recover from sleep debt?

It depends on how far behind you are. A US expert panel suggests it can take several days to recover from even one hour of lost sleep, so a few nights of slightly longer sleep usually works better than one long lie-in.

Is sleeping in on the weekend bad for you?

Not if it's modest. An extra hour or two can help after a short week. Sleeping much later than usual can shift your body clock and make Monday morning harder.

Can Thrive show if I'm short on sleep?

Thrive shows hours slept and your sleep Quantity, Quality, Regularity and Timing each night, so you can see a run of short nights across the week.

For more answers, see Questions.