The dreaded time change is approaching: October 27 will be delayed. It is the moment when, despite that extra hour in bed, it seems that winter is approaching.
While an hour may not seem like a lot, it can have a big impact on our biological clocks, which, in turn, can affect everything from digestion to blood pressure.
In fact, it has been suggested that it would be better for our health if we eliminated seasonal time changes altogether.
Earlier this year, the American Academy of Sleep Medicine called for eliminating twice-yearly clock changes (one in spring and one in fall), on the grounds that they cause a misalignment between the outside world and our biological clock, or circadian rhythm. , stating that this ‘has been associated with risks to physical and mental health and safety, as well as risks to public health.’
The good news is that there are steps you can take to minimize such disruptions. And while you may not like the prospect of darker nights, the fact that the clocks go back actually means that we realign with a more natural rhythm for our bodies, so you may find it easier than the change of clock in spring. (Unless you’re a natural morning person, who may find this more difficult; more on this later.)
Changing the clock twice a year can cause health problems such as increased heart rate and blood pressure, and has been linked to an increase in traffic accidents.
Research has long shown that the “spring preview” in March, which moves us into British summer time, sometimes called daylight saving time, is linked to a sharp increase in health problems such as heart attacks and strokes. , as well as with hospital admissions due to ear problems. fibrillation (an irregular heart rhythm) in the following days.
And a 2019 review of seven previous studies by the University of Ferrara in Italy suggested that it’s disruption to our circadian rhythms and lack of sleep that causes increased heart rate, blood pressure, and inflammation levels.
The two time changes each year have also been linked to an increase in traffic accidents, possibly because the disruption of sleep and our biological clocks leaves us feeling “jet lagged” and less alert.
For example, a 2020 study in the journal Current Biology found a 6 percent increase in car accidents after the spring time change, while a review of RAC police data from 2018 suggests there is an increase in traffic accidents after clocks go back. ‘ to standard time in October.
“Each cell in the body has its own clock,” explains Dr Gisela Helfer, associate professor of physiology and metabolism at the University of Bradford.
«We also have a master clock in the brain – the suprachiasmatic nucleus (a small group of nerve cells) – and what it does is coordinate those rhythms, like an orchestra conductor.
Dr Gisela Helfer, assistant professor of physiology and metabolism at the University of Bradford, says that while our brain resets quickly to turn the clocks forward or back, our tissues and organs need more time to catch up, so they suffer a Kind of jet lagged for a week or so
‘Each physiological process has a specific time when it works best. For example, when we sleep we are not eating, so we do not need as many hormones to help us with digestion.
“But when we wake up and our bodies are waiting to break the fast, we need insulin and for the entire gastrointestinal tract to be prepared for the food to come. The problem is that our brain quickly resets to the new time, but our tissues and organs, like our digestive system, they have to catch up. Then we’re out of sync for a week or two, and that’s when you get that jet lag feeling.’
A study published in the Journal of Clinical Gastroenterology in 2020 suggested that an altered circadian rhythm can cause stomach problems, especially constipation. The change in sleeping patterns can also trigger a migraine or headache.
To manage the transition smoothly, Dr Kat Lederle, sleep specialist at The London General Practice, suggests that in the six days before the clocks go back in autumn, we should go to bed about ten minutes later, progressively each day. In spring we should do the opposite.
“And do the same with meal times and anything else you can change in small steps (for example, a training program),” he adds.
This helps because the timing of our meals and exercise sends signals to our biological clocks that help them keep pace. But why is a time change of just one hour so disturbing?
It has to do with changing light levels. Our bodies need darkness at night to prepare for sleep by producing melatonin, while light does the opposite.
Daylight sends direct signals to the “master clock” through special light receptor cells in the eyes, which the body takes as a signal to suppress melatonin, in addition to telling the other clocks in our body to be in mode. day.
While we might associate daylight saving time with bright summer mornings, the reality is that the clock changing in spring means it’s actually darker when we wake up in April. While for most people, after the October change, when they wake up there will initially be more light. Dr. Lederle explains, “From a light exposure perspective, it’s healthier when we’re on standard time because there’s more light in the mornings.”
Clock changes can also affect us differently depending on our ‘chronotype’, that is, our genetic propensity to be a lark (early to bed, early to rise) or an owl (late to bed, late to rise).
Larks appear to have more difficulty with autumn change than with spring change, according to a 2007 study by the University of Groningen in the Netherlands, published in the journal Current Biology. But owls and people who don’t belong strongly to one chronotype or another find it harder to jump.
While you might think that earlier darkening nights would be better for larks, they find it harder to adapt, possibly because they don’t feel the benefit of lighter mornings since they get up before dawn anyway. And they are unlikely to enjoy an extra hour in bed.
Others who probably won’t benefit from the extra hour of sleep with the fall time change include anyone who shares their home with beings whose brains don’t understand the concept of clock time: that is, babies, dogs and cats. That is, unless you also make an effort to gradually adjust light exposure and feeding times beforehand.
Sleep specialist Dr. Kat Lederle suggests slightly modifying your bedtime and meal times in the six days before the clocks go forward or backward to minimize disruption to your “confusing” internal system.
The good news, however, is that babies adapt more quickly to “falling backwards” (and wake up less during the night when clocks go back), Sleep magazine reported in May of last year; this is possibly because standard time coincides better. with our natural circadian rhythm.
All of which has fueled debate over whether we should limit ourselves to just one time of year all year.
After all, daylight saving time was not introduced until 1916 to make better use of the long summer days and save fuel (for coal-fired lighting, for example) during World War I.
In 2022, the American Medical Association called for an end to daylight saving time, saying, “Committing to standard time has health benefits and allows us to end the biannual tug-of-war between our biological clocks and alarm clocks.”
Dr. Lederle agrees: “When we suddenly have this imbalance, our brain becomes confused as to what process should be activated and what should be stopped.
“That’s when we see an increase in health conditions: it affects heart rate, blood pressure and digestion, and in the long term we see an association between altered clocks and cancer risk plus fertility risk for women.”
And while some modern advocates suggest choosing one or the other (British Daylight Time or Standard Time), “100 percent, I would stick with Standard Time,” Dr. Lederle says. ‘It doesn’t seem like it, because the days are shorter, but it is the healthier of the two. It’s better for our sleep.
If we decided to permanently stick to British Summer Time, where clocks are permanently moved forward, sunrise on the shortest day of the year would be 9:03am, and who wants that?