Daylight Saving Time and Your Health
Plus, Steps to Saving Zzz’s
Published February 2021
While 60% of countries worldwide follow standard time year-round, most of the U.S. switches between standard and daylight saving time (DST) annually. This biannual change has sparked debates about its health impacts.
“There has always been a debate regarding daylight saving time,” says Phyllis C. Zee, MD, PhD, sleep medicine specialist and chief of Sleep Medicine in the Department of Neurology at Northwestern Medicine. “Over the last decade, science has shown that the transition between standard time and DST is linked to adverse health effects. The big question now is, should we have permanent standard time or permanent DST?”
Dr. Zee advocates for eliminating time changes and adopting year-round standard time.
What Is Daylight Saving Time?
DST occurs from March to November when most U.S. states, including Illinois, turn clocks forward one hour. However, states like Hawaii and Arizona do not observe DST.
In states that follow DST, the “spring forward” in March results in losing an hour of sleep, which can significantly impact the body for days or even months.
“The transition between standard time and DST is associated with adverse health consequences,” says Dr. Zee.
A Potential Barrier to Sleep
Sleep health relies on the balance between two processes:
- Sleep homeostasis: The increasing desire to sleep from waking up until bedtime.
- Circadian rhythm: The body’s natural 24-hour cycles, including the sleep-wake cycle.
Your circadian rhythm is regulated by exposure to bright light during the day. “With DST, between March and November, there’s less morning light and more evening light, which can disrupt your circadian rhythm,” explains Dr. Zee.
When your internal clock is out of sync with the sun’s clock, you may feel tired in the morning and awake at night, disrupting sleep homeostasis and overall sleep health.
“If we adopt permanent standard time, our internal clocks will align better with the Earth’s rotation, seasonal changes, and the sun’s clock,” says Dr. Zee.
A Broader Health Hazard
“We know that sleep deprivation is bad for your physical and cognitive health,” Dr. Zee notes. She explains that transitioning to DST can lead to short-term health problems such as sleep issues, fatigue, and blood pressure changes, akin to prolonged jet lag. Teenagers and “late starters” are particularly vulnerable due to their tendency to sleep through morning light, further disrupting their circadian rhythms.
DST can also have long-term health effects. Studies show it is linked to:
- Depression
- Slowed metabolism
- Weight gain
- Cluster headaches
DST has been associated with increased risks of cognitive, mental health, digestive, and heart disorders. For those already suffering from these conditions, DST can exacerbate symptoms.
In the week following the switch to DST, research shows an increase in:
- Cardiovascular disease, with a 24% higher risk of heart attacks
- Injuries, including a 6% rise in fatal car accidents
- Stroke rates, which increase by 8%
- Mental health issues, with an 11% rise in depressive episodes
- Digestive and immune-related diseases, such as colitis, which increase by 3% in women over 60
‘Til next time, Green Living Tribe!
