The change to summer time on Sunday that causes millions of people to lose an hour of sleep is not just an annoyance. It can significantly increase health risks, experts say.
A recent study in Finland suggested that the rate of occurrence of ischemic stroke (the most common form of stroke) is 8% higher during the two days following the change Second Sunday in March. According to the same study, cancer victims are 25% more likely to have a stroke during this period and people over 65 are also more at risk by 20%.
“Previous studies have shown that disturbance of the internal clock due to other reasons (eg change in work schedules) and fragmentation of sleep are associated with a higher risk of stroke, Dr. Jori Ruuskanen, the author of the study. However, we did not know if the risk of stroke is affected by DST. ”
According to Dr. Ruuskanen, the greater risks observed during his team’s research diminish after the time change because our body and our internal clock are gradually adapting.
CNN writes that this study is not the only one to warn of the potentially negative consequences of the switch to daylight saving time.
According to another study quoted by the American channel, on Mondays and Tuesdays following the change of spring time were also associated with an increase of cases of heart attacks, that is to say of 10%. The study dates from 2012 and was conducted by a team from the University of Alabama, Birmingham.
The National Sleep Foundation, quoted by CNN, recommends, to counter the effects of the change of time, to sleep longer Sunday morning and take a nap in the afternoon.
Friday night, at 10 pm TVA News, neuropsychologist Dr. Johanne Lévesque explained that the switch to daylight saving time on Sunday is more difficult than the return to normal time in the fall.
“In the fall, it’s as if our cycle, our internal clock, naturally fits nicely,” said Dr. Lévesque. At this point in the year, which is a lot more difficult, we lose an hour, so we lose sleep. And this loss, even if it makes us gain in light, would seem to be much more traumatic, in quotation marks, for our body which is recovering with difficulty. ”
Ms. Lévesque added that the disturbance of the internal clock is also associated with other phenomena “such as the production of cortisol in the morning that allows us to get up”.
“You know, our body temperature reaches its lowest point around 5 am and shortly there is cortisol that is sent in large quantities to help us wake up, but by the time this adaptation takes place, […] our body did not have the small boost, the small surplus of cortisol to allow us to wake up. So it’s difficult in the morning. ”
If there are difficulties at the time of daylight saving, however, there are benefits, particularly in terms of long-term mood, added Dr. Lévesque.