TEXARKANA, Texas — Many Americans are annoyed by the annual spring ritual of sacrificing an hour to daylight saving time, but its more serious effects — increased health risks — go beyond inconvenience.
The sudden shift in how our bodies process light, and its impact on the human sleep cycle, can turn “springing forward” into a health crisis tipping point, said Dr. Matthew Ramage, a family and primary care physician with Texarkana’s CHRISTUS Trinity Clinic.
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Measurable effects of daylight saving time include an increase in car crashes, some fatal; increase in missed medical appointments; a higher risk of stroke and hospital admissions; an increased risk of mood disturbances; and disruption of the body’s circadian rhythm, or internal clock, impairing sleep quality and leading to sleep loss, according to the American Academy of Sleep Medicine.
The evidence for such risks is ample and strong enough that AASM for years has advocated for action making standard time permanent.
“Humans are light-powered organisms, if you want to call it that. We take a lot of physiologic cues and psychological cues from the sunlight,” Ramage said. “Sun and blue light that we get from the sun change our chemistry and set our clocks.”
When light — especially high-energy light in the blue range of the spectrum — enters the eye, it stimulates a structure in the hypothalamus portion of the brain called the suprachiasmatic nucleus, which regulates the sleep cycle.
“What that does is just tell your brain, ‘OK, you’re awake, you’re awake, you’re awake,'” Ramage said.
An opposite process occurs as darkness falls in the evening. Another brain structure, the pineal gland, begins to release the hormone melatonin, beginning the sleep cycle. Our heart rates slow, our body temperatures decrease, and we start feeling sleepy.
The time change in the spring directly disrupts this rhythm.
“It’s darker in the morning when we should be getting that light hitting our eyes and telling us to be awake, and it’s lighter in the evening. We’re exposed to that bright light when it’s time to start winding down. So it completely unravels what we’re wanting to do,” Ramage said.
One result is a surge of the hormone cortisol in the morning. That affects the vagus nerve, which plays a large role in controlling autonomic functions such as respiration and heart rate. Blood pressure can spike.
“That brake pedal for our heart is going to be inhibited, causing our heart rates to rise. And so if you’re already on the cusp of having the risk for heart attack or stroke, that’s just going to nudge you over the edge, Ramage said.
The resulting cardiac crises, as well as regular medical appointments missed because of the time change, cause an increase in emergency room visits corresponding to daylight saving time.
Another concern is negative psychological events brought on by changing the light-darkness cycle.
“During daylight saving time, that added stress that people experience does put them over that tipping point. So if they’re having stress and a poorly managed depression or poorly managed anxiety, that can cause them to spiral. It can be that inciting event to where we do see a lot of crisis intervention care that is needed for that susceptible population,” Ramage said.
Vanishing an hour overnight can also exacerbate existing sleep problems and cause dangerous fatigue. Motor vehicle accidents and safety-related job injuries increase.
The best way to help avoid health problems associated with daylight saving time is to practice good “sleep hygiene” and be as well-rested as possible before the time change.
Ramage recommends a consistent bedtime routine to regulate circadian rhythm, including dimming lighting when it is time to wind down for the night. He emphasized avoiding television, cellphone, tablet and computer screens, which emit a lot of blue light the brain interprets as daylight.
“It’s our little artificial sun right in our face before we’re trying to go to sleep,” he said.
Lowering bedroom temperature is also a good idea, as it lowers body temperature, one of the primary physiological cues that it is time to fall asleep.
Basic health care — both physical and psychological — can also go a long way toward preventing a sudden crisis.
Those with mental health challenges should “speak up, because what we don’t want to do is have people suffer in silence and get into these crisis situations where they’ll do a drastic measure for the short term that will have long-term implications , like hurting themselves,” Ramage said.
People should also seek care for health risks such as high blood pressure, high cholesterol and physical inactivity.
“Just do what you can to not be on the cusp, to have something as silly as setting our clocks forward be the thing that breaks you.”