“How did you sleep?”
It is one of those deceptively polite questions, like “How are you?” or “Did you enjoy the fish?” to which the only socially acceptable answers are “Fine” and “Yes, lovely”.
Most of us reply by counting hours. Seven and a half. Six, but solid. Eight, but up twice for the loo. We speak of sleep as though it were a bulk commodity – weighed, measured, stacked like firewood.
But the latest thinking from the sleep boffins suggests something rather irritating: it’s not just how long you sleep. It’s when.
Yes. We are being told – by serious people with degrees – that going to bed and waking up at the same time every day (give or take half an hour) may be as important as the number of hours you manage.
And before you protest that you are retired and answer to no alarm clock, allow me to gently suggest that your body still does.
Jean-Philippe Chaput, a professor of medicine at the University of Ottawa, has been banging on about “sleep consistency” – the idea that your bedtime and wake time should be steady, including weekends.
Large observational studies have linked irregular sleep schedules with increased risks of cardiovascular disease, obesity, depression, anxiety and even dementia.
One 2020 study of nearly 2,000 adults in the US found those with the most irregular sleep patterns were more than twice as likely to develop cardiovascular disease as those who kept regular hours.
In 2024, a UK study of more than 88,000 adults found people with the most erratic sleep schedules were about 50 per cent more likely to develop dementia than those with middling regularity.
Now, this doesn’t mean a late night at your granddaughter’s 21st will instantly fell you. These are observational studies – they show patterns, not iron laws. But the pattern is consistent enough (amusingly) that sleep scientists now broadly recommend regular bed and wake times to protect metabolic, mental and cardiovascular health.
Annoying, isn’t it? The answer was discipline all along.
The likely culprit is your circadian rhythm – your internal 24-hour clock.
This little marvel regulates not only sleep and wakefulness but hormones, appetite, metabolism, mood, immune function and cardiovascular activity. It likes routine. It thrives on predictability. It is, in essence, a Labrador.
When you lurch between 10pm one night and midnight the next – rising at 6am on Monday and 8:30am on Thursday – your circadian rhythm is forced to recalibrate. Hormones like cortisol and melatonin are released at odd times. Hunger signals wander off piste. You may find yourself peckish at 10:30pm or oddly wired at midnight.
Dr Andrew Varga of Mount Sinai in New York has noted that irregular sleep can push people towards late-night eating, digestive mischief and weight gain. It’s not dramatic. It’s cumulative. And that, at our age, is the issue.
You don’t feel dreadful in the morning. You just feel … slightly off. And slightly off, over years, becomes something more consequential.
Quite. You have earned the right not to be dragged from your bed by a shrieking alarm clock.
But retirement is precisely when sleep regularity can drift. No commute. No school run. No office hours. Tuesday becomes indistinguishable from Saturday.
And while that sounds gloriously liberating, your biology still prefers rhythm.
As we deviate from our usual sleep times – across days, weeks, months – the more health risks appear to climb.
Not because the body is petty. Because it is programmed.
We are not talking military precision. Experts allow a 30-minute buffer either side. Bed at 10:30pm most nights? Fine. Up at 6:30am? Lovely. Drift to 11pm occasionally? You’ll survive.
The key is not to swing wildly between night owl and lark.
Helpful tricks include:
An evening wind-down alarm (an alarm to go to bed — deeply humbling, but effective).
Morning light exposure at the same time each day — ideally outside, even if it’s cloudy.
Keeping weekends broadly similar to weekdays.
Avoiding the creeping creep of “just one more episode”.
Light in the morning is especially important. It tells your body when the day begins, which sets the timer for when melatonin — the sleep hormone — will arrive that evening. Think of it as pressing “start” on the 24-hour washing machine that is you.
We all love the idea of freedom. A late night here. A lie-in there. The delicious anarchy of not caring what the clock says.
But it turns out the clock cares what you do.
Going to bed and waking up at roughly the same time each day may not be glamorous. It will not earn you bragging rights at brunch. It may, however, quietly protect your heart, your waistline and your brain.
Which is to say: wildly exciting? No.
Wildly sensible? Infuriatingly, yes.
So tonight, at the same time as last night, I suggest you toddle off to bed.
Your circadian Labrador will be thrilled.