Can Better Sleep Mean Catching Fewer Colds?

Lack of sleep affects your immune system.

Medically Reviewed by Michael W. Smith, MD on January 19, 2010
5 min read

Mother knows best -- at least it appears that way when it comes to lack of sleep. It turns out that lack of sleep really may make us more prone to catching colds and the flu. And that includes the H1N1 virus.

“It is an old wives’ tale that if you don’t sleep well, you will get sick, and there is some experimental data that shows this is true,” says Diwakar Balachandran, MD, director of the Sleep Center at the University of Texas M.D. Anderson Cancer Center in Houston.

Some 50 million to 70 million American adults suffer from sleep disorders or the inability to stay awake and alert, according to the CDC. Though it’s not always easy to do, getting adequate sleep can help keep our immune systems primed for attack.

Not getting enough sleep has been linked to a laundry list of mental and physical health problems, including those that stem from an impaired immune system. Our immune system is designed to protect us from colds, flu, and other ailments, but when it is not functioning properly, it fails to do its job. The consequences can include more sick days.

The relationship between lack of sleep and our immune systems is not quite as straightforward as mom made it out to be, however. The immune system is pretty complex. It is made up of several types of cells and proteins that are charged with keeping foreign invaders such as colds or flu at bay.

“A lot of studies show our T-cells go down if we are sleep deprived,” Balachandran says. “And inflammatory cytokines go up. ... This could potentially lead to the greater risk of developing a cold or flu.”

In simple terms, sleep deprivation suppresses immune system function. Or, as Balachandran puts it, “The more all-nighters you pull, the more likely you are to decrease your body’s ability to respond to colds or bacterial infections.”

Sleep loss not only plays a role in whether we come down with a cold or flu. It also influences how we fight illnesses once we come down with them.

For example, our bodies fight infection with fevers. “One of the things that happens when we sleep is that we can get a better fever response,” Balachandran says. “This is why fevers tend to rise at night. But if we are not sleeping, our fever reaction is not primed, so we may not be waging war on infection as best we can.”

Studies have shown that people who are sleep deprived also get less protection from flu vaccines than those who are getting adequate sleep, Balachandran says.

John Park, MD, a pulmonologist who specializes in sleep medicine at the Mayo Clinic in Rochester, Minn., agrees. “We know that our immune response is suppressed when we are sleep deprived and that we develop less antibodies to certain vaccines if we are sleep-deprived,” Park says. “It takes longer for our body to respond to immunizations, so if we are exposed to a flu virus, we may be more likely to get sick than if we are well rested when vaccinated.”

Sleep loss also plays a roll in our ability to fight off serious health conditions. Research suggests that sleep-deprived people are at higher risk of dying from heart disease, according to Balachandran. “The more sleep loss, the higher your levels of C-reactive protein (CRP) will be,” he says. CRP is a marker of inflammation, and inflammation may play a role in heart disease.

People who sleep less are actually more likely than their well-rested counterparts to die from all causes. “Studies show that people who get about seven hours of sleep a night have the best survival, and if we get less than six hours of sleep a night, our mortality seems to increase,” Balachandran says.

It appears that some people may do better on less sleep than others. “If you have a strong immune system, it may take longer for you to get run down if you are not sleeping,” says Susan Zafarlotfi, PhD, clinical director of the Institute for Sleep and Wake Disorders at Hackensack University Medical Center in New Jersey. “Some people may be able to drink a cup of coffee from Starbucks or Dunkin' Donuts and readjust. But if you have a weak immune system, you will likely be more prone to infection if you are not getting enough sleep.”

But Balachandran says the bottom line is this: “We live in a 24-7 society and everyone has two jobs and is bombarded with media. So sleep seems expendable. But proper sleep is a fundamental component of a healthy lifestyle.”

Balachandran offers some sleep hygiene tips for better health. “Go to sleep at the same time every day and wake up at the same time,” he says. “Make sure that your bedroom environment is well-suited for sleep. This means shutting off the computer and TV before bed.”

If you aren’t getting adequate sleep, Park says the most important question is: why? “Is it by choice or necessity, or because you physically are unable to sleep?” he asks. “If you physically can’t sleep due to insomnia or another underlying health problem, visit your doctor or a specialist to see what treatments are available.”

Treatment may include medications and sleep hygiene tips such as avoiding caffeine after lunch, not consuming alcohol within six hours of your bedtime, and not smoking before bed. You may also learn relaxation and cognitive behavioral therapy techniques for changing actions or thoughts that may be hurting your ability to sleep.