The Biggest Sleep Research Breakthroughs of 2021

It was an important year for the science of sleep — including the dangers of shift work, the impact of COVID-19, and the cost of sleep disorders.

A bed with a lamp, books and glasses on a bedside table. 2021 was a great year for sleep research.
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2021 has been full of events that have made all of us toss and turn. From the ongoing pandemic to political unrest, economic woes, natural disasters, and more, it’s no wonder that 2 in 3 Americans have reported sleep problems since 2020. The good news is that sleep scientists are delving ever further into why we sleep, the importance of sleep, and what keeps us from getting our Zzz’s.

While no one can wave a magic wand to make all our sleep woes disappear (if only!), the advances researchers made during 2021 may help all of us understand how to get a better night’s rest.

We’ve rounded up a few of the biggest breakthroughs in sleep made in the past year that will help set the stage for 2022.

Sleep in the pandemic age

For a second straight year, COVID-19 dominated news headlines, and the pandemic also influenced sleep research. Worries about the virus itself have kept more than a few people awake into the wee hours of the morning, but new studies are showing that COVID-19 has even impacted our dreams.

A study of 90 adults in Italy compared several sleep factors during lockdown and after. Results published in the Journal of Sleep Research found that individuals took longer to fall asleep, woke up more times during the night, had more lucid dreams (when a dreamer, though asleep, is aware they are dreaming), and were more likely to remember their dreams the following day during lockdowns than afterwards.

What you can do: Dreaming is your brain’s way of consolidating, regulating, and problem-solving your emotions, including stress. If COVID-19 has impacted your dreams, start a dream journal. You may uncover answers from your sleep.

Sleep disorders can also increase a person’s chances of severe COVID-19 illness and death. An international study of healthcare providers found that every additional hour of sleep at night decreased the chances of COVID-19 infection by 12%. Those with sleeping difficulties, such as insomnia or disrupted sleep, were not only more likely to become infected but also to report severe illness.

In a separate study, scientists at the Cleveland Clinic analyzed data from 5,400 patients who received a coronavirus test at the Clinic and had a sleep study available. The researchers found that although individuals with breathing difficulties and/or low oxygen levels during sleep weren’t more likely to be infected with the virus, they were 31% more likely to be hospitalized or die from the condition, according to results published in JAMA Network Open.

What you can do: Sleep helps your immune system boosts the effects of the COVID-19 vaccine. Now more than ever is the time to prioritize sleep so you can get the full 7 to 9 hours of rest you need.

Dangers of shift work

Our 24/7 society means that jobs often require people to work at all hours of the day — and night. Over the past decade, researchers have linked regular nighttime shift work to issues like heart attacks, ulcers, depression, obesity and high blood pressure. But a small clinical trial, funded by the National Heart, Lung, and Blood Institute, found that eating only during daytime hours, even when working through the night, can keep blood glucose levels normal, potentially reducing the risk of diabetes.

What you can do: When you eat also contributes to the regulation of your circadian rhythms, especially if you eat on a consistent schedule. No matter how you decide to set up your mealtimes, remember to avoid eating before bed.

Directors of the Shift Project found that a 2017 Seattle law requiring hourly service employees (who comprise a disproportionate number of shift workers) to know their schedules two weeks in advance resulted in more predictable working hours. This, in turn, led to an 11% increase in workers reporting good or very good sleep when compared to other cities without such a law, according to results published in the journal PNAS. These results support new evidence-based guidelines on shift work from the American Academy of Sleep Medicine and Sleep Research Society.

These recommendations were designed to help employers develop the best policies to balance productivity with worker fatigue and sleep needs. Rather than a one-size-fits-all policy, the groups outlined a series of principles that will help employers evaluate risks and identify countermeasures.

What you can do: Plan ahead for known sleep disturbances. While sleep banking — the practice of getting enough sleep, in anticipation of future sleep deprivation — has limited effectiveness, taking time to extend your sleep may help improve your tolerance against sleep deprivation.

Sleep duration

When it comes to sleep, researchers have found that we’re a lot like Goldilocks. Too little sleep isn’t good for our health and well-being, but neither is too much.

Sleep specialists at Henry Ford Hospital in Detroit evaluated data from 14,079 participants followed for an average of 7.5 years. Results found that individuals who slept less than 6 hours per night or more than 7 hours had a higher risk of death from a cardiac-related problem compared to those who got between 6 and 7 hours of sleep. Scientists still aren’t sure why, but they suspect that overly long or short sleep duration may increase inflammation in the body.

Nor do naps make up for nighttime sleep loss, according to a SLEEP journal study. Researchers found that 30- to 60-minute naps during the day did not have any measurable impact on relieving the cognitive effects of sleep deprivation.

What you can do: Not everyone needs the same amount of sleep. To find out exactly what your personal sleep hours are, record how many hours you’ve slept each night and how you feel each day. Focus on days when you wake feeling refreshed (preferably without an alarm).

Cost of sleep disorders

Our collective troubles with shut-eye aren’t cheap, either. Researchers at Mass Eye and Ear (part of Mass General Brigham) analyzed data from a survey of over 22,000 American adults and found that 5.6% of respondents reported at least one sleep disorder.

These people reported an additional $7,000 in healthcare costs each year, giving them a bill that is 60% higher than their well-rested counterparts. Crunching the numbers, the scientists say that all of this means that sleep disorders cost at least $94.9 billion in health care costs each year. The study, published in the Journal of Clinical Sleep Medicine, is probably an underestimate of the true cost since it doesn’t factor in additional costs, such as time off from work and school and decreased productivity.

What you can do: Invest in the right sleep gear and optimize your bedroom to be cool, dark, and quiet. A good cooling mattress on an adjustable base can help with night sweats, chronic back pain, sleep apnea, and more. A white noise machine may help reduce sleep disruptions in the environment like street cars or your partner’s snoring.

Sleep issues in children

While many of us (*raises hand*) want nothing more than to sleep like a baby, children aren’t immune to sleep difficulties. A study in Nature Communications found that children who snored 3 or more times per week (according to their parents) showed significant brain changes linked to impulsivity, learning difficulties, and hyperactivity.

MRI data from more than 10,000 9- and 10-year-old children showed that regular snoring thinned the gray matter (the dense tissue of neurons in the brain) in the frontal lobes of the brain, which help regulate emotions and attention. The researchers say that snoring can disrupt oxygen flow to the brain and disrupt sleep, both of which may play a role in these brain changes. Scientists are planning a follow-up study to see what happens to these children’s brain and behavior over time.

What you can do: Teach your children good sleep hygiene and help them keep their bedtime routine as best as possible. Plan ahead for travels or holidays but also be patient and flexible with your child’s response as they navigate unexpected routine changes.

The year ahead

There is still much to learn about sleep, and many studies are presently underway. Current studies are evaluating sleep apnea screening devices, sleep and yoga interventions, and behavioral sleep intervention, as well as the impact of background noise and bright lights on sleep.