No matter the specific virus, nearly every sickness has one recommended treatment in common: lots of rest. Getting extra sleep when you’re sick doesn’t just give you a few hours of respite from unpleasant symptoms: Sleep is like medicine for the immune system, ultimately helping you make a full recovery from an illness.
“Sleep is the only time of anyone’s day or night where we have restoration processes happening. It’s the only time when we replenish our energy sources, which are exhausted when you’re sick,” explains Allison Brager, Ph.D., a neurobiologist with expertise in sleep and circadian rhythms and a wellness coach with a focus on athletics.
Here’s a closer look at the importance of sleep when you’re sick, along with tips for getting more rest when you’re under the weather, whether you’re battling the common cold, COVID-19, or something else.
How sleep helps you heal
The supreme exhaustion you feel when you’re sick isn’t only because you might have been up all night coughing — it’s your body’s way of telling you it needs rest. This feeling of tiredness and overall sluggishness is an adaptation called “sickness behavior,” and it forces you to slow down. (Some fitness trackers, noting elevated heart rates and temperatures, might call it “rest mode.”) The rest allows your body to channel all its resources toward breaking a fever, fighting pathogens, and recovering from a virus, rather than helping you power through a typical active day. It also benefits the entire community by keeping you home, rather than out in the world where you can potentially spread germs to others.
But sleep is even more important than simply resting. There’s also a close connection between sleep and the immune system that can impact your recovery from an illness. When you’re asleep, your body releases proteins called cytokines, some of which communicate with cells in the immune system to help knock out a pathogen. Interestingly, some cytokines help promote sleep. Giving in to those feelings of fatigue helps the body make more cytokines and fast-track your recovery.
“If you’re not sleeping well, the body doesn’t produce cytokines as productively,” notes Julia Kogan, a health psychologist who focuses on behavioral sleep medicine at the Department of Veterans Affairs. “The lack of sleep sets you up to potentially be more sick and makes it harder for your immune system to fight things off.”
Sleep also has an impact on the cells the body uses to fight off viruses, which could impact how well you recover from a sickness. Results of a 2019 study suggest that sleep helps T cells (a type of white blood cell) more easily stick to infected cells and destroy them. What’s more, slow-wave sleep (also known as delta sleep, our deepest stage of sleep) and the circadian rhythm induce hormonal changes that help send T cells to the lymph nodes and stimulate an immune response against a pathogen.
Keeping your head plopped on the pillow may be important for the functioning of natural killer cells, another type of immune cell that can attack tumor cells, as well as cells that have been invaded by a virus. Research shows that even modest amounts of sleep loss (like restricting sleep time to just four hours in a night) cause natural killer cell activity to drop significantly. That could mean feeling sicker for longer in the short term, and increasing your risk factors against autoimmune issues, too, including potentially increasing your risk of dying from cancer over the long run.
More research is needed to figure out exactly why these virus-fighting immune responses occur during sleep, but experts say it may be because the body doesn’t have the same demands on its resources as it does when we’re awake.
“Being awake is extremely stressful for the body,” explains Brager. “When you’re sleeping, it can instead focus on keeping the immune system healthy.”
Kogan adds: “Sleeping gives the immune system an opportunity to function at its best.”
How much sleep do you need when you’re sick?
It’s clear that your body needs more sleep when you’re unwell, which can help your immune system and recovery. But just how much more sleep should you get when you’re sick?
“There’s no set amount, but the more sleep you can get when you’re sick, the better,” advises Brager.
If you’re looking for a magic number, aim for more than nine hours. That’s the amount of sleep that may be appropriate for people with illnesses to get on a regular basis, according to the American Academy of Sleep Medicine and Sleep Research Society, so it’s probably a safe target if you’re dealing with a brief sickness.
But don’t stress over trying to get that exact right amount of sleep (especially if you’re going over it). As long as you’re giving your body the sleep it’s asking for, you’re doing the right thing for your recovery, says Brager.
“When the body wants to be awake, it will be awake. It has its own set points,” she says.
In addition to getting enough sleep, timing your sleep can also be important when you’re sick. You can take naps throughout the day to boost the overall amount of sleep you get over a 24-hour period. But if possible, try to still aim for a good long continuous stretch of sleep over the course of the night when you’re sick.
“It’s better to get good nighttime sleep because that’s when you’ll hit all the stages of your sleep cycle,” Brager says, including that restorative slow-wave sleep.
Tips for sleeping better when you’re sick
Good sleep can seem pretty elusive when you’re congested, achy, coughing, shivering, or simply feeling just plain miserable. But there are some things you can try to get better sleep when you’re sick.
- Don’t eat too close to bedtime: “Eating no less than three hours before going to bed can help your body focus on sleep instead of digesting,” says Kogan. If your sickness has sapped your appetite, try to take a few bites of something nourishing several hours before hitting the hay. “If your body is hungry, that can wake you up more frequently, as well,” Kogan adds. Try to minimize processed foods and focus on vegetables, fruits, and lean protein, as well as soups.
- Avoid screens at night: “A lot of people want to watch movies and veg out when they’re sick, but artificial light from technology is never sleep-promoting,” warns Brager. “Reading books, listening to music, or doing something that doesn’t involve screens can help you maximize your sleep.”
- Use a humidifier: Dry air during the winter can lead to dry sinuses and other symptoms that make it even harder to sleep when you’re sick. Using a humidifier can increase the moisture in the air and potentially ease some respiratory symptoms. If the congestion has settled in your chest, you can also try running a hot shower to create a makeshift steam room.
- Consider a vitamin D supplement: “There’s some evidence that shows vitamin D supplementation can help with sleep…and it’s good for the immune system,” says Brager. But before adding any supplement to your regimen, talk with your doctor to make sure it’s the right move for you.
- Stay hydrated: Research has uncovered a potential link between shorter sleep duration and inadequate hydration. Since common sickness symptoms like sweating, diarrhea, and vomiting can make you more susceptible to dehydration, try to increase your intake of fluids when you’re under the weather.