In many parts of the world, people collectively reset their clocks twice a year. Depending on the season, clocks are either wound an hour forwards, or an hour backwards - a practice designed to maximise the overlap between our waking hours and the available daylight.
Now, members of the American Academy of Sleep Medicine (AASM) Public Safety Team and Board of Directors have published an advisory calling for the practice of daylight saving to be abolished.
"Daylight saving time is less aligned with human circadian biology - which, due to the impacts of the delayed natural light/dark cycle on human activity, could result in circadian misalignment, which has been associated in some studies with increased cardiovascular disease risk, metabolic syndrome and other health risks," they write in the Journal of Clinical Sleep Medicine.
"It is, therefore, the position of AASM that these seasonal time changes should be abolished in favour of a fixed, national, year-round standard time."
Their paper is focused on the US, citing health statistics connected with the changing of the clocks in spring - from standard time to daylight saving time. This is when the clocks are wound back an hour, so that everyone loses an hour, usually from their sleep schedule.
Ostensibly, the major economic reason for daylight saving time (DST) is to reduce energy usage, an effect that has been found to result in savings from 0.5 to 1 percent to a potential energy use increase in some areas as dependence on home heating and cooling rises.
It's also thought that daylight saving time allows additional daylight leisure time in the warmer months; however, if it does, people don't seem to be making use of it.
These inconclusively demonstrated benefits, according to AASM, are not worth the human lives lost to daylight saving. Conversely, there may be significant health benefits, both physical and mental, to a regular time schedule.
"Existing data support the elimination of seasonal time changes in favour of a fixed, year-round time," the members wrote.
"DST can cause misalignment between the biological clock and environmental clock, resulting in significant health and public safety-related consequences, especially in the days immediately following the annual change to DST.
"A change to permanent standard time is best aligned with human circadian biology and has the potential to produce beneficial effects for public health and safety."
The human circadian rhythm is the 24-hour biological cycle that, among other things, regulates our sleep-wake cycle - although this cycle can be artificially altered, as shift workers well know. As we also know from studies on shift workers, such alterations can lead to dangerous and health-degrading sleep disorders.
AASM believes that a similar effect is at play when our sleep time is abruptly shifted back an hour. And there's certainly plenty of evidence that the DST switch can have effects a lot worse than being more sleepy than usual for a few days while you adjust.
Some effects are relatively mild. Immediately after the shift to daylight saving time, people are less productive, and slack off at work more. Students have been found to perform more poorly on tests.
It gets worse from here. Judges are more likely to issue harsher penalties in their courtrooms - so you'd best hope your court date doesn't fall immediately after the spring DST shift. Medical professionals make more mistakes, too.
Several studies have found that fatal accidents of all kinds temporarily increase immediately following the spring shift to daylight saving time. Non-fatal workplace accidents also increase; and those accidents are more likely to be serious.
You're more likely to have a heart attack following the spring shift; in fact, total mortality of a population has been found to rise. And, tragically, male suicide rates increase in the weeks following the shift to daylight saving time.
The effects after the autumn shift back to standard time are not nearly so pronounced. However, it does still compromise sleep and the rest-activity cycles.
Daylight saving time isn't even that popular. Only around 70 countries still observe it, and that number is dropping. The European Union voted to abolish it last year (although they're yet to set a date for when that will come into effect).
And, according to a survey of 2,000 people conducted by AASM in July, 63 percent of respondents wanted to abolish daylight saving time, compared to just 11 percent who wanted to keep it.
"There is ample evidence of the negative, short-term consequences of the annual change to daylight saving time in the spring," said medical doctor Kannan Ramar, director of AASM.
"Because the adoption of permanent standard time would be beneficial for public health and safety, the AASM will be advocating at the federal level for this legislative change."
The advisory has been published in the Journal of Clinical Sleep Medicine.