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The end of summer -

Daylight saving time (DST) in the United Kingdom and Europe is set to end on Sunday, October 31. In the United States and Canada, DST ends on the first Sunday in November.

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Daylight saving time -

Europe, the UK, Canada, and the United States are more the exception than the rule. Most countries do not observe daylight saving time—the practice of advancing and winding back clocks seasonally in the spring and fall. In fact, only about a third of the world's countries practice daylight saving time.

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Calls to end DST -

Many scientists are calling for the end of the practice, citing negative impacts on health and the economy.

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Time Use Initiative -

In fact, ending seasonal clock change by 2026 is one of the 12 suggested measures included in the EU manifesto on Time Policies launched by the Time Use Initiative to ensure the right to time in Europe.

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State policy issue -

And the topic is subject of fierce debate in the US, with the National Conference of State Legislatures (NCSL) reporting that "state legislatures continue to grapple with the vexing and multifaceted state policy questions regarding the biannual changing of the clocks."

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The chronobiologist's point of view -

Meanwhile, chronobiologists in Great Britain, experts that study biological rhythms, claim that shifting the day by just an hour can have massive consequences; they are calling for DST to be ditched entirely.

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Clocking the issue -

So are biannual clock adjustments a literal waste of time? What exactly are the experts worried about? Well, our internal body clock, or circadian clock, is integral to this discussion.

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Circadian rhythms -

Circadian rhythms, also known as internal clocks, control important bodily processes. They help us know when we are hungry, thirsty, and sleepy.

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Our body clock -

Circadian rhythms also help regulate things such as body temperature and hormones.

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Sleep-wake cycle -

The cycle of sleep and wake is one of the most obvious circadian rhythms in humans. Any disruption to this cycle can affect how well you sleep, when you sleep, and how you function while awake.

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Out of rhythm -

Putting the clocks forward every year can knock the sleep-wake cycle out of sync with the environment, scientists suggest. This in turn causes a raft of problems they say are linked with daylight saving time.

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Cancer risks -

For example, putting the clocks forward every year has been associated with increased cancer rates.

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Risk levels according to time zones -

According to a study undertaken by the National Cancer Institute (NCI) in the United States, where you live within your time zone could be associated with a slightly increased risk of developing certain cancers that have been linked to disruptions of the biological clock. Research indicated that those living in the west of a time zone have higher risks of leukemia, stomach cancer, lung cancer, breast cancer, and more.

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Circadian misalignment -

Beside elevated cancer risks in certain situations, disruption to our body clocks, or circadian misalignment, is also linked with increased risk of cardiovascular disease, diabetes, and obesity.

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Mental health issues -

Psychiatric conditions such as depression, bipolar disorder, schizophrenia, and attention deficit disorders can result from disrupted circadian rhythms.

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Biological imbalance -

On a more general level, a misaligned body clock can induce changes in appetite, feeding habits, and metabolic functions.

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Interrupted work flow -

Circadian disruption has also been blamed for underperformance in the workplace.

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Crash course -

Worryingly, according to a study by the Association for Psychological Science published in ScienceDaily, the risk of fatal traffic accidents can increase by up to 6% following the spring daylight savings time transition.

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Back in the day -

Adjusting daily schedules to the sun is nothing new. It's known that ancient civilizations often divided daylight into 12 hours regardless of daytime, so that each daylight hour became progressively longer during spring and shorter during fall. The Romans managed their own version of DST by using a water clock, or clepsydra.

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First DST proposal -

We have New Zealand entomologist and shift-worker George Hudson (1867–1946) to thank for modern daylight saving hours. He proposed DST in 1895 as a method of seasonal time adjustment to take advantage of an extra two hours of daylight.

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Sunny cities -

In 1908, Port Arthur (pictured) and Fort William (now collectively known as Thunder Bay) in Ontario, Canada, became the first cities in the world to adopt DST, the desire being to simply enjoy an extra hour of summer sun.

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A method of saving energy -

Eight years later in Europe, the German Empire and its First World War ally Austria-Hungary implemented DST to use less power for lighting and to save fuel for the war effort.

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British Summer Time -

In England, construction worker William Willett (1856–1915) had already promoted the idea of British Summer Time so that mornings have one hour less daylight, and evenings one hour more when Great Britain and most of its allies adopted DST in 1916.

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Standard Time Act -

DST was first implemented in the US with the Standard Time Act of 1918, a wartime measure for seven months during the Great War in the interest of adding more daylight hours to conserve energy resources.

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Going back in time -

The spring clock change, where clocks are fast forwarded by one hour, is the time change that is usually most disruptive to our health. But what are the effects on our well-being when the clocks go back?

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Less sleep -

While switching clocks back in the fall helps avoid some of the morning gloom, the fact is our circadian rhythms are once again subject to disruption.

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An hour's difference -

While an alarm goes off at 8 am, say, your body clock is actually reading 7 am. Pushing your system outside of its normal range, even by an hour, and forcing it to function earlier than it would expect to can cause problems.

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Monday morning blues -

The additional stress of it being a Monday morning doesn't help, but the real risks involved in rising earlier are more or less the same as those incurred in spring. People with high blood pressure, high cholesterol and diabetes, or who are smokers or overweight, are especially vulnerable.

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No need to worry -

As a rule, those that are relatively healthy and not sleep deprived needn't worry too much about the clocks changing.

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Tips for better shut-eye -

A useful tip is to go to bed slightly later and get up slightly later, say by 20 minutes or so, for a couple of days before the switch. This should make it a bit easier to get out of bed on Monday morning.

Sources: (Pew Research Center) (Time Use Initiative) (NCSL) (Sleep Health Foundation) (NCI) (Association for Psychological Science) (Northern Ontario Travel) (Daily Mail) (British Sleep Society) 

See also: What happens to your body when you don't sleep enough?

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