The modern science of sleep

Every human is born knowing, instinctively, how to sleep. Yet only recently have scientists begun to understand our universal need for nightly rest.
We now know that sleeping habits affect our judgment, perception, long-term memory, metabolism and quality of life. No wonder we try all sorts of remedies to sleep better.
Healthy sleep patterns can improve our moods, buttress our minds and even extend our lives — but not always in the ways we assume. And losing sleep can have dire consequences. What do we really know about our need to doze?
Zonking out before midnight can protect our “circadian rhythm,” or biological sleep cycle. Harvard researchers concluded that falling asleep between 10 and 11 p.m. may decrease our risk of heart disease, even though others found that “night owls” have better cognitive functioning. Men can add five years to their lives with consistent quality sleep, according to a 2023 study; women can add 2.5 years. Better sleep correlates with heart health, immunity, muscular resilience and memory.
That’s how many Americans experience short-term insomnia. In the long run, up to 70 million suffer from this and other disorders like narcolepsy and sleep apnea, which correlate with high blood pressure, heart disease and diabetes. Snoring at any volume is a bigger risk factor for heart attack and stroke than smoking or high cholesterol, but one recent paper found that some people snore louder than others for unknown reasons.
Sleep-deprived people gained weight that much faster in a recent study; another linked poor sleep habits with obesity. One study found that participants with irregular sleep patterns were 34 percent more likely to develop Type 2 diabetes. Another, published by University College London, found that subjects in their 50s and 60s who got six hours of sleep or less each night were 30 percent more likely to develop dementia later in life than those who got seven hours or more.
The National Sleep Foundation recommends an ambient sleep temperature of 60 to 67 degrees Fahrenheit, though we’re still allowed to use blankets. There is also such a thing as an ideal sleep surface, according to a 2021 study from Italy: a medium-firm mattress, which “promotes comfort, sleep quality” and alignment better than the alternatives.
Americans spend that much annually on sleep aids, from antihistamines to Ambien and melatonin gummies. That number is projected to nearly double by 2032, although sleeping pills don’t always lead to a good night’s rest and could shorten our lives by about five years. They also spend about $23 billion on sleep tech, from FitBit tracking devices to “smart beds” and enhanced blindfolds — a number projected to quintuple by 2033. But if you can’t fall asleep after 20 minutes in bed, the Mayo Clinic suggests getting up and doing something relaxing before trying again.
Going 24 hours without sleep impairs driving like a blood alcohol concentration of 0.10 — twice the legal limit in Utah. “Drowsy driving” causes 8,000 deaths in the U.S. every year. Harvard researchers note that sleeping six hours per night for nine days, rather than seven to nine, can result in a similar level of impairment on day 10.
Nearly all American adults consume caffeine every day via coffee, energy drinks and sodas. They experience insomnia, snoring and fatigue more often than those who avoid drinking caffeine. Alcohol is known to harm the quality of rest. Early findings also suggest that marijuana use may negatively impact sleep over time.
A 2019 paper found this annual spike linked to daylight saving time, when clocks spring forward from 2 a.m. to 3 a.m. There is a growing body of literature linking sleep disturbance and suicide, with one recent paper from researchers at the University of Arizona arguing that better sleep could be an effective strategy for suicide prevention.
Parents lose that much sleep the year after having a baby. Meanwhile, jet lag costs about a day of recovery for each time zone crossed. And screen time has an inverse relationship with sleep duration. If our life choices make us tired enough, our bodies force us to rest through “microsleep,” when we lose conscious control of ourselves for 30 seconds or less, even if our eyes stay open.
That’s the most any person has gone without sleeping. Guinness World Records stopped keeping track in 1996, citing the harmful effects of sleep deprivation. One early study suggests that impact may originate in our guts. Fruit flies deprived of sleep started producing cell-destroying molecules in their digestive tracts; when given antioxidants to neutralize these molecules, the flies never had to sleep again.
This story appears in the October 2024 issue of Deseret Magazine. Learn more about how to subscribe.