Canadian Health & Lifestyle

Your Health vs Daylight Savings Time

alarm clocks lined up for daylight saving time

Ready to spring forward this weekend?

About a third of us aren’t happy about it. And a whopping two-thirds of us would like to stop the twice-yearly time changes altogether.

Springing forward may be a bigger deal than we think. Researchers are finding that the March time change is more than just an inconvenience, it may be having a lasting health impact.

Advancing the clock forward by one hour each spring may increase heart attacks in adults, and cause poor sleep quality in adolescents.

By comparison, there are no health effects linked to changing back to standard time. It seems only the shift to daylight saving time has an unwanted effect on health. Researchers think the negative effects stay with us throughout daylight saving time.

That’s because, standard time and daylight saving time are not the same.

At noon during standard time, the sun is typically directly above, which is closest to natural light. But when it shifts to daylight saving time (March through November), the clock change influences when natural light shines each day; one hour later in both the morning and evening.

But sunlight during the morning is key for setting up the body's natural cycle. It wakes us up, increases our alertness and possibly enhances our spirits via increased cortisol levels, a hormone that regulates stress; or maybe by influencing the amygdala, the brain regions connected to emotion.

Because of this and other factors, the American Medical Association has asked for permanent standard time to be instituted, with Mexico following suit. Canada continues discussions. Many argue that permanent standard time would bring countless health, productivity, and energy saving advantages.

The main perk of daylight saving time is the extra hour of light in the late afternoon or evening, yet this extended exposure to light later in the day may come at a cost.

Extended evening light is linked to postponement of the brain’s production of melatonin, a hormone that induces sleepiness.

For adolescents, the body's response to evening light is delayed due to an already altered release of melatonin. This causes teens to be particularly vulnerable to persistent sleep difficulties.

Geography may also have an impact during daylight saving time. One study showed that individuals on the west-side of a time zone enjoyed less sleep than their east-side counterparts because of receiving light later in the morning and later at night.

This study suggested that people living on the west border had higher rates of obesity, diabetes, heart disease, and breast cancer, a lower per capita income, and increased health care costs.

Other research has found that rates of certain cancers to be elevated in the western portion of a given time zone. This health phenomenon may be caused by a combination of fatigue and body clock desynchronization known as circadian misalignment (that typically occurs when people structure their daily routines, such as work or sleep, around time schedules and not natural light cues.

Are you ready for the time change? In 2023, clocks will advance one hour at 2 am on Sunday, March 12.