Everyone wants to know the magic number. Seven hours? Eight? Whatever the wellness influencer of the week reckons?
Fair enough, the number matters. I’ll get to it. But I’ve come to think the duller habit matters just as much, maybe more, and it’s the one nobody wants to hear about. Go to bed and get up at roughly the same time. Every day. Saturdays too (sorry).
So how much sleep do you actually need?
For adults aged 18 to 60, the US Centers for Disease Control and Prevention says seven hours or more. It shifts a little as you get older: seven to nine hours between 61 and 64, then seven to eight from 65.
Back in 2015, the American Academy of Sleep Medicine and the Sleep Research Society got 15 sleep specialists in a room (figuratively, it was a year-long review) and they landed in the same place. Their consensus statement says six hours or less, night after night, isn’t enough for an adult to stay healthy and safe. What I found interesting is they didn’t cap it. Young adults, people who are unwell, anyone paying back a sleep debt? More than nine hours can be perfectly appropriate.
Do most people hit seven? Nope. In the CDC’s 2024 survey data, 30.5% of American adults said they usually got less than that. Among 35 to 64 year olds it crept up to roughly a third, which makes sense when you think about who’s juggling kids, jobs and ageing parents. Around 18% said they struggled to stay asleep. About 15% couldn’t nod off in the first place.
The problem with averages
Now for the bit that actually changed how I think about this.
A team at the Adelaide Institute for Sleep Health, part of Flinders University, put sensors under the mattresses of 67,254 adults and tracked them for roughly nine months. No sleep diaries, no guessing. Actual nightly data. The study came out in Sleep Health in 2024.
Just 15% of them consistently got seven to nine hours on five or more nights a week. Fifteen per cent!
The part that got me, though? Even the people whose average looked healthy spent 28% of their nights under seven hours. The researchers also found weekend sleep ran about 28 minutes longer than weeknights, which is the catch-up effect in black and white.
You probably know the pattern because most of us live it. Six hours Tuesday. Six and a half Wednesday. A late one Friday, then a glorious 10am wake-up on Saturday that you tell yourself evens it all out. Your sleep app shows a tidy weekly average. Your body just rode a rollercoaster.
Why your body cares about timing
There’s a clock running inside you, and it’s a creature of habit. It takes its cues from light, from when you eat, from when you move and, crucially, from when you wake up. Shift those around by two hours every weekend and you’re basically handing yourself a mild dose of jet lag on Saturday, then flying home again on Monday morning.
Maybe that’s why the first sleep tip on the CDC’s list is the least glamorous one: same bedtime, same wake time, weekends included.
Making it stick (without becoming a monk)
Fix the alarm, not the bedtime. You can’t always control when you get to bed. Dinner runs late, the footy goes to extra time, your sister calls. The morning is easier to lock down because the alarm does the heavy lifting. Pick a wake-up time you could live with on a Sunday and hold it for a couple of weeks. Bedtime tends to sort itself out once you’re naturally drowsy earlier.
You can still sleep in. Just keep it to about an hour past your usual time rather than surfacing at lunchtime. Completely cooked after a big week? A short nap in the early afternoon usually does less damage to the routine than a three-hour lie-in.
Get some daylight early. Morning light is one of the strongest signals your internal clock gets, and you don’t need anything fancy. Coffee on the back step counts. So does the walk to the bus.
Then there’s the wind-down. The CDC suggests turning devices off at least half an hour before bed, and keeping the bedroom quiet, relaxing and cool. Honestly, the single most useful thing I’d suggest is charging your phone in the kitchen. Try it for a week.
Coffee after lunch is worth a second look too. The CDC recommends skipping caffeine in the afternoon and evening, because it lingers in your system far longer than it feels like it does. Same story for a big dinner or a few drinks late at night. Alcohol might knock you out, sure. It’s the 3am wake-up that gets you.
Oh, and move a bit during the day. Regular exercise is on the CDC’s list. A brisk walk is plenty.
Give it two weeks before you judge it
The first Saturday with an alarm is miserable. No point pretending otherwise.
Most people find it gets easier after a week or so, once the body clock catches up. One bad night doesn’t mean it isn’t working. Look at the fortnight as a whole. Are the 3pm slumps less brutal? Are you on coffee number two instead of four?
When to see someone
Sometimes routine isn’t the problem. If you’ve had trouble falling or staying asleep for weeks, if your partner says you snore like a leaf blower or seem to stop breathing, or if you’re drowsy enough to worry about driving, book in with your GP.
This stuff matters beyond feeling flat, too. The CDC links ongoing short sleep with a higher risk of type 2 diabetes, heart disease, high blood pressure and stroke, plus more car accidents. Which, when you put it like that, makes a boring bedtime look like a pretty good deal.
This article is general information only and isn’t a substitute for advice from your doctor.
Leave a Reply