The Surprising Health Effects of Daylight Saving Time
Staying up late or waking up early might seem like no big deal for most of us. But for some, losing just one hour of sleep due to daylight saving time could have a lasting effect on health and well-being.
When daylight saving time starts in March, clocks “spring forward” by 60 minutes. But when DST ends the first Sunday in November, clocks are turned back, meaning less daylight during waking hours.
Jennifer Wolkin, a clinical neuropsychologist who specializes in stress reduction and mental health, says both adjustments can throw off sleep.
“The loss of just a single hour of sleep takes a physical toll on our bodies,” says Wolkin. “Our internal clocks, often called our circadian rhythms, are scrambling to adjust to changes in our principal time cue: light.”
In other words, when the time changes in the spring and fall, our circadian rhythms are thrown off, resulting in increased stress and poor quality sleep. This, in turn, leads to things like poor work performance, increased hunger, and general unhappiness, according to a 2012 study from the Journal of Applied Psychology. According to another 2014 study from Economics Letters, researchers found that the time change left employees tired and stressed, which negatively impacted workplace performance and overall life satisfaction.
This disruption can be particularly dangerous in the fall, says Wolkin.
“[The start of] daylight saving time at least offers the advent of spring and summer, with its warm temps and light evenings,” she says. “It’s a time when people become more active and more social, both of which are key for fostering overall wellness.”
But in fall months, even though falling back means we gain an extra hour of sleep, “we are on the cusp of cold and dark winter days, which don’t offer the same kind of accessibility and willingness for exercise and socializing.” Rates of seasonal affective disorder, anxiety, and depression also climb during the fall, says Wolkin. Falling back due to DST means waking when it’s darker out, and could trigger or worsen some of these seasonal issues.
But spring isn’t much safer, science shows. Researchers have found an uptick in car crashes, workplace accidents, and cardiovascular incidents such as heart attacks and strokes, directly after the start of DST in the spring. Apparently, people with underlying health problems are more susceptible to the stress that is kicked off by the time change. In a 2012 study from the University of Alabama at Birmingham, researchers found that heart attacks actually increased by about 10 percent in the week after DST started in the spring.
After a “period of adjustment” of about a week, the health issues—sleep disruption, moodiness, poor work performance, cardiovascular problems—returned to normal, says Wolkin. In the meantime, she encourages patients to take extra care of themselves, particularly in the fall. Regular exercise, talk therapy, and mood lamps can all help patients who struggle to adjust to the time change.
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