Why we have it and how it impacts health 

It’s almost time to turn the clocks back an hour as daylight saving time ends on Sunday, Nov. 5.

But regaining an hour of sleep comes at a cost to our physical and emotional health, medical experts warn.

What is daylight saving time (DST) and why do we have it?

Daylight savings is the practice of setting clocks ahead during spring and summer to afford us more daylight hours.

Though not all societies choose to participate, a form of DST is seen throughout North America, Europe and some South American countries.

DST was adopted globally more than a century ago as a way to reduce daily energy use during the darkness of winter, as more sunlight during waking hours meant less need to burn down candles. Since then, several countries have dropped the habit in favor of year-round standard time, as many studies have shown the practice may be putting people at a detriment.

DST-induced sleep loss is hard on the body

Research from 2020 found that the fall-back hour was connected to a 6% increase in car wrecks overall with a 15% rise in freeway crashes, 9% of non-intersection crashes, 28% for nighttime crashes (28%) and single-vehicle crashes respectively, and crashes in urban areas also rose by 12%.

“The scientific evidence points to acute increases in adverse health consequences from changing the clocks, including in heart attack and stroke,” said Johns Hopkins sleep expert Adam Spira. 

“The consequences of insufficient sleep include decreases in cardiovascular health, increases in diabetes and obesity, poorer mental health, lower cognitive performance, and an increase in the risk of motor vehicle accidents,” Spira added.

DST causes a disruption to our body’s circadian rhythm, which dictates sleep patterns in a 24-hour span. And being awake before the sun’s rise is no good for mental health.

“We don’t really know the specific reason for increases in heart disease and stroke during the daylight saving time change, but it likely has something to do with the disruption to the body’s internal clock, or its circadian rhythm,” said Dr. Donald Lloyd-Jones, president of the American Heart Association 

When DST ends, SAD begins

The end of DST also marks the start of seasonal depression, medically referred to as seasonal affective disorder (SAD). It impacts up to 5% of the adult population while another 10-20% also suffer from mild winter blues, according to The Cleveland Clinic.

Symptoms of SAD, which typically show up in the fall and subside in the spring, include increased fatigue and low energy, loss of interest, low libido and hopelessness.

A lack of sunlight brought on by the time change is linked to a chemical shift in the brain, experts believe.

“Melatonin, a sleep-related hormone, also has been linked to SAD,” writes Johns Hopkins. “The body naturally makes more melatonin when it’s dark. So, when the days are shorter and darker, more melatonin is made.”

One surefire way to counteract SAD is to find ways to soak up the sun when you can, according to Johns Hopkins.

Taking vitamin D supplements, which our bodies produce when skin is exposed to sunlight, is another way to boost the mood-regulating hormone serotonin during months of overcast, the Mayo Clinic advises. Light therapy with UV lamps is another option.

These are some things to be aware of with daylight savings and the effects of SAD and the time change overall as colder weather approaches.

How to prepare your body for daylight savings

Dr. Charles Kinsella of Franciscan Health suggests a few methods to prepare one’s self for the earlier darkness and recommends trying to stay in as much of your usual routine as possible. “It’s a pretty quick adaptation,” he said, also offering these pointers on getting adjusted.

• Get as much light as you can before DST begins
• Go to be earlier each night in anticipation of the time change
• For heart health, avoid caffeine to deal with daytime sleepiness
• Avoid napping as it will interfere with the sleep cycle
• Try to not sleep in on weekends and instead use that time to get light exposure
• Limit screen time before bed