Reduce your risk of stroke when the clocks go forward

There’s a vital extra hour of daylight this weekend that could make a real difference to those whose health may be affected by the clock change. David Cox explains

‘Changing the clocks, even by a single hour, disrupts our circadian rhythms’

Every single year, the annual ritual of putting the clocks forward by one hour in the spring is associated with a dramatic spike in heart attacks, strokes, and overall deaths.

If we go by past research, people are at an 8 per cent higher risk of an ischemic stroke – the most common form of stroke – and 24 per cent more likely to suffer a heart attack in the two days following the daylight saving time transition.

Workplace injuries are also 6 per cent more likely, while rates of road traffic accidents are likely to be up 30 per cent at the start of next week. Patients in hospitals will also be at a greater risk of medical errors, based on findings from a 2021 study which found that safety-related incidents at healthcare facilities across the United States spiked after the springtime daylight savings shift.

According to sleep scientists, this is all because changing the clocks, even by just a single hour, disrupts our circadian rhythms – the 24-hour clock which the body operates on – in a similar manner to jet lag.

“It’s a shock to the system, losing that hour of sleep,” says Beth Malow, a neurology professor at Vanderbilt University Medical Centre in the US. “Your whole circadian alignment gets thrown off, and that abrupt shock triggers the clotting of proteins, causing heart attacks, strokes and increased inflammation.”

Chris Fox, a sleep researcher and professor at the University of Exeter Medical School, says that those at most risk are people with any pre-existing health condition. “If you’re slightly overweight, a smoker, you’ve got diabetes, sleep apnea, a chronic respiratory disorder, or you’re taking medication for several conditions, you’re more vulnerable to the impact of the clock change,” he says.

However, Prof Fox also points out that all of us can be impacted to some extent by the clocks going forwards. “I always feel a bit exhausted for a few days afterwards which shows the effect it can have on us,” he says. But there are measures we can all take which can help mitigate the impact of daylight saving time on our health.

Limit your amount of screen time on Saturday night

A newly published study in the journal Stroke has found that continuous excessive exposure to artificial light in the evening can raise your risk of blood clots and other biological processes which impair blood flow to the brain, so increasing the chances of a stroke.

Given how daylight saving time already impacts our body clock, Prof Fox recommends that people should avoid too much screen time tonight; for example, avoid scrolling through social media posts on your smartphone or watching the latest Netflix series in bed. This is because the screens of smartphones and tablets emit blue light, which affects a part of the brain called the pineal gland, which is often dubbed the “third eye” and which plays a key role in regulating the sleep-wake cycle.

“The pineal gland operates on a daily clock and produces hormones which affect sleep and wakefulness,” says Prof Fox. “If you’re getting too much blue light in the evening, then it prevents that little clock from telling you it’s time to go to sleep. And during the daylight savings time shift, you need to be getting as much quality sleep as you can to minimise the effect.”

Get outside on Sunday morning

But just as artificial light can cause us problems, exposure to daylight can help the body to re-regulate itself and adjust to the new time shift. This is because daylight stimulates the production of vitamin D which in turn stimulates melatonin, the hormone responsible for regulating our body clock. Getting outside can even help with regulating your blood pressure after the time shift, as blood pressure is sensitive to changes in circadian rhythm.

“You might feel really sluggish on Sunday and Monday, but instead of reaching for that coffee or taking a nap, it’s best to get yourself outside,” says Prof Malow. “Getting some daylight is great in the morning because it’ll help reset your clock, and what you’re doing is to try and align your brain and body with the outside world.”

Have breakfast or lunch by the window

If you have a busy day planned and there isn’t time for a Sunday morning stroll, you can still get some of the benefits of daylight, simply through sitting by the window.

“Going outside is the best, but the next best step is natural light through your windows, particularly in the morning because exposure to light at that time of day is so important,” says Prof Malow.

Try a melatonin supplement

Finally, if you always feel particularly groggy when daylight savings time rolls around, Prof Fox suggests trying a melatonin supplement, which is known to aid with jet lag by stimulating the body to realign its circadian rhythms.

While you can only buy melatonin tablets in the UK with a doctor’s prescription, anyone can order melatonin patches or creams online. Many of these topical forms are designed to be slow release, so after rubbing them on your skin the day before the clocks go back, they will gradually release melatonin over a period of time, helping to ensure you have as restful a night as possible.

“In theory, that approach could work because it’s about normalising the circadian rhythm and giving you a nice relaxing night’s sleep, and that might help overcome that change,” says Prof Fox.