Even before the pandemic, more than a third of Americans weren’t getting the recommended seven plus hours of nightly sleep. And by certain estimates, as many as 68% of Americans say they just aren’t getting enough rest.
“Most of the systems in our body are predicated on some process of renewal or need for sleep,” explains board-certified sleep medicine researcher W. Christopher Winter, MD, the author of The Sleep Solution: Why Your Sleep Is Broken and How to Fix It. “Sleep is a fundamental aspect of our thinking, our ability to function, and our immune system. It impacts pretty much everything we need to survive.”
So turn off your phone, close the shades, and hop into bed early tonight — here’s what a lack of sleep can hurt:
Your immune system. “There’s a very strong link between sleep and the immune system in general,” says Michael Awad, MD, of Northwestern Medicine and Peak Sleep. “The body repairs just about every cell in the body when it comes to sleep. Sleep deprivation lowers the body’s ability to mount an immune response.”
Sleep loss is linked to a higher risk of infection, according to the Centers for Disease Control and Prevention (CDC). One study found that restricting a person’s sleep for four hours a night for six days, followed by sleeping 12 hours a night for seven days, can lead to a greater than 50% decrease in the production of antibodies to a flu vaccine. Basically, your body just can’t mount the usual immune response when you’re wiped out.
Lack of sleep can also lower your immune system’s ability to fight tumor cells and lead to the generation of inflammatory cytokines. These proteins are secreted by the immune system and can cause the development of metabolic and cardiovascular disorders.
Your heart. One study of nearly 117,000 people published in the European Heart Journal found that people who slept less than six hours a night were at a greater risk of developing heart disease than their well-rested counterparts. And getting irregular sleep—that is, having no consistent bedtime and wake time—can raise your risk of having some kind of cardiovascular event, including stroke, congestive heart failure, and coronary heart disease, according to a study published in the Journal of the American College of Cardiology.
There are a “tremendous number of mechanisms” at play here, Dr. Winter says. “When you are sleep deprived or have fragmented sleep, your blood vessels lose, to some extent, the ability to expand and contract to regulate things,” he says. People also tend to be at a higher risk of developing high blood pressure when they don’t get enough sleep, Winter says, which can be tough on your heart.
Sleep deprivation can also increase cholesterol levels and general inflammation throughout your body, leading to the formation of plaque in the blood vessels, Dr. Awad says. “When blood vessels start to form plaque, the heart has to work harder.”