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Always Sick? It Might Be Your Sleep

Medically Reviewed by Michael W. Smith, MD on July 21, 2021

Are you feeling a little under the weather? It could be tied to how you sleep.

Studies show that if you don't spend enough time sleeping, or the sleep you get isn't good quality, you're more likely to get sick when you're exposed to something like the common cold or the flu. Not only that, but when you get sick, you may stay sick longer.

Sleep and Your Immune System

What is the connection between sleep and your body's defense against illness and infection? The first thing to know is that it works both ways.

Without good sleep, your body makes fewer antibodies to help you fight infection. It also releases fewer proteins called cytokines. Among other things, cytokines fight off inflammation and infection -- and help regulate your sleep. Fewer antibodies and cytokines give you less ammunition to battle a cold or the flu.

Once you have an infection, your body needs more cytokines than normal to help fight off your illness. If you aren't getting enough rest, your body can't make enough to do what it needs to do to get you healthy. So it can take longer for you to get well.

Scientists aren't sure how or why your sleep changes when you're sick. One theory is that the body tries to get you to sleep more when you're ill so that it can do things to heal itself, such as generate a fever.

The two-way street between your immune system and sleep can be seen with vaccinations. Some vaccines contain weakened bacteria. They are designed to trigger your immune system and prepare it to fight infections when they happen. And research says that vaccines work better when you get enough sleep after you've been vaccinated.

Sleep Disorders

Having a sleep disorder can make it even harder to fight off illness or recover when you get sick. Here’s a look at some common sleep disorders and how you can treat them:

Insomnia. This disorder causes trouble falling or staying asleep at night. Your doctor may prescribe medication and therapy for long-term insomnia.

Sleep apnea. There are different types of sleep apnea, but the most common type is obstructive sleep apnea. This is when your muscles relax as you sleep so that the soft tissue in the back of your throat collapses and blocks your airway. When that happens, you stop breathing for 10 to 30 seconds or more until you wake up briefly. This cycle can be repeated many times over the course of a night, interrupting your sleep every time.

Weight loss, sleeping on your side, and other lifestyle changes may improve this condition. You could also need a continuous positive airway (CPAP) machine, which keeps your airway open while you sleep.

Restless legs syndrome (RLS). RLS creates discomfort in the legs and an impulse to move them as you fall asleep. Lifestyle changes like adjustments to your sleep habits, exercise, compression devices, massages, hot baths, and medication are all RLS treatments.

Narcolepsy. With narcolepsy, you’ll feel very drowsy during the day and have problems staying awake. There’s no cure for narcolepsy, but lifestyle changes and medication can ease your symptoms.

Illnesses Linked to Poor Sleep

Research shows a connection between a lack of sleep and several health conditions.

Type 2 diabetes. Better sleep could equal improved blood sugar control. Research links how well you sleep and how much of it you get to your hemoglobin A1c (blood sugar) levels.

Heart and blood vessel disease. When you have a sleep disorder, your odds of having illnesses of the heart and blood vessels (cardiovascular disease) also go up. People with sleep apnea may be more likely to have high blood pressure, stroke, and irregular heartbeat than those who don’t have it.

Obesity. A lack of sleep may also cause you to gain weight, researchers find. They’ve discovered the link between poor sleep and obesity across all ages but say it’s especially worrisome in kids. Kids need sleep for proper brain growth. When they don’t get it, it could impact the energy and appetite control center of the brain (called the hypothalamus).

In turn, obesity affects your ability to sleep well. Researchers think that the extra weight affects your circadian rhythm and metabolism in ways that cause you to sleep poorly. They’ve found that people who are overweight often have trouble falling asleep or have insomnia. There’s also a link between obesity and feeling sleepy or fatigued during the day, even if you’ve had undisturbed rest the night before.

Depression. Sleep and depression have a two-way relationship. Poor sleep is a symptom of depression and other mental health problems. Having a mental health disorder can disrupt your sleep. Researchers have studied people with sleep apnea and depression and find that if you treat the sleep disorder, it eases the symptoms of depression.  

COVID-19. When you’re sleep-deprived, it’s harder for your body to fight off illnesses that affect the immune system like COVID-19. Those who have recovered from COVID-19 also report trouble sleeping. Some people with long-haul COVID-19 have insomnia and other sleep issues, even after mild COVID symptoms.

Getting Your ZZZs

Adults need between 7 and 9 hours of quality sleep every night. Teens should get from 8-10 hours. And anyone younger than that should get at least 9 hours (preschoolers and younger, at least 10).

As important as the total number of hours, though, is the quality of your sleep. Snoring and feeling tired throughout the day are just a couple of signs that the ZZZs you're getting may not be good enough.

If you have constant sniffles and think your crummy sleep may be to blame, check with your doctor or a sleep specialist. They can help you make your nights as restful, and as healthy, as they should be.

WebMD Medical Reference

Sources

SOURCES:

National Institute of Neurological Disorders and Stroke: "Brain Basics: Understanding Sleep."

Colton, HR. Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem, National Academies Press, 2006.

Mayo Clinic: "Lack of Sleep: Can It Make You Sick?" “Sleep disorders.”

Physiological Reviews: "The Sleep-Immune Crosstalk in Health and Disease."

National Institute of Allergy and Infectious Diseases: "Overview of the Immune System."

Pfluger's Archive: "Sleep and Immune Function."

Nature Reviews Neuroscience: "How (and why) the immune system makes us sleep."

Sleep Foundation: "How Sleep Affects Your Immunity," “Mental Health and Sleep,” “Insomnia,” “Sleep Apnea,” “Restless Legs Syndrome (RLS),” “Narcolepsy,” “Obesity and Sleep.”

CDC: "Vaccines: The Basics," "How Much Sleep Do I Need?" "Key Sleep Disorders," "Sleep and Chronic Disease," "Tips for Better Sleep."

National Heart, Lung, and Blood Institute: “COVID and Sleep: Better Slumber During the Pandemic May Help Protect Your Health.”

American Academy of Sleep Medicine: “Obstructive Sleep Apnea.”

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