Can sleep help fight COVID-19?
Want to reduce your COVID-19 risk? It would be best if you slept more.
Until a vaccine is available, the key to avoiding COVID-19 is reducing one’s risk of infection as much as possible. Better sleep can help. Sleep is a simple way to bolster the immune system against colds, influenza, and other respiratory infections.
Observations about sleep and its health benefits date back at least 2,000 years. Aristotle’s publication On Sleep and Sleeplessness in 350 B.C. suggested that digestion in the stomach produces hot vapours that lead to sleep, and that people with fevers experience something similar, driving them to snooze to help the healing process.
While the vapours idea did not pan out, decades of scientific evidence show that sleep is a solid way to bolster the immune system against colds, influenza, and respiratory infections. That work suggests that sleep may be a powerful tool to fight the pandemic - and not just by reducing the likelihood or severity of infections. Sleep may ultimately boost the effectiveness of COVID-19 vaccines when they become available, and a flurry of studies are underway measuring how much of a health buffer we gain against the coronavirus by hitting the sack.
“We have a lot of evidence that if you have an adequate amount of sleep, you definitely can help to prevent or fight any kind of infection,” says Monika Haack, a psycho-neuroimmunologist at Harvard Medical School. “How many deaths can you prevent if you sleep properly, or how much less is the severity of your symptoms? I think that needs more research.”
Until a vaccine is available, the key to avoiding COVID-19 is reducing one’s risk of infection as much as possible. As new data roll in on sleep and this disease, scientists hope to better elucidate the complex workings of the immune system, while also providing clearer guidelines on how to use sleep as a weapon to stave off the pandemic.
Growing evidence also shows that sleep deprivation impairs a person’s ability to fight off a disease once they are infected. In several studies, people with sleep disorders, people who catch less than five or six hours of shut-eye per night, and people with low levels of sleep efficiency (the percentage of time spent snoozing during the night) report higher rates of respiratory illnesses, head colds, and related ills.
the compelling case that sleep gives the immune system a real boost. This is especially true for antibodies, which are generally long-lasting proteins that the body makes in response to pathogens (and vaccines). Antibodies help the body remember those infections.
In one of the first such studies from 2002, one group of people slept about eight hours for four nights before getting a flu shot, then slept the same amount for the two nights after the shot. Ten days later, researchers reported that the participants’ influenza antibody levels were more than twice as high as those in people in another group who had slept only four hours per night over the same period. Sleep deprivation can also reduce antibody responses to hepatitis A, hepatitis B, and H1N1 swine flu vaccines. In some studies, one night is all it takes.
Those antibody advantages lead to measurable health outcomes, even in the long term. One study linked better sleep before getting the hepatitis B vaccination with a lower likelihood of getting the disease over the next six months.
Given the intense interest in developing a COVID-19 vaccine that will squelch the pandemic, a simple behaviour that could make immunizations more effective would be welcome news. At Walter Reed, researchers are developing a COVID-19 vaccine, and when its phase one clinical trial begins this winter, Colonel Capaldi says, they plan to have one group of participants sleep up to 10 hours a night for several nights before getting the vaccine. If snoozing leads to a better vaccine response compared to people who are chronically sleep-deprived, future work could look at whether getting more sleep with assistance from medication might provide the same benefits.
Researchers at Walter Reed, UCSF, and other institutions are now sifting through mountains of data to connect sleep with COVID-19 risk. Nothing has been published yet, but Haack says she has reviewed multiple upcoming studies on the topic, and the results appear promising.
Sleep is far from the only factor that affects susceptibility to illness, says Carnegie Melon’s Cohen. Exercise, social support, stress levels, smoking, alcohol consumption, and other factors also explain why only a subset of people get sick when exposed to any virus, according to an analysis Cohen published in 2020.
Still, experts advise prioritizing sleep for people who have the option, given its influence on infection risk. Sticking to a consistent sleep schedule is one effective way to get higher quality sleep, Prather says. So is relaxing before bed by dimming lights, turning off screens, and taking a break from the news. Cohen recommends people sleep at least seven hours a night to improve their chances of staying healthy during the pandemic.
“Over and over, we show that people who got insufficient amounts of sleep were more likely to get sick when we exposed them to a virus,” he says. “It clearly plays a role in health and wellbeing.”