What happens when you don't get enough sleep

According to Emerson Wickwire, a sleep medicine specialist at the University of Maryland Medical Center, sleep "affects every organ system and bodily function, from your heart to your brain, and even the way that you think and feel each day."

"The reasons aren't entirely clear, but [sleep is] an essential thing that we all do," said Rafael Pelayo, a sleep specialist at Stanford University. "Something remarkable happens when you sleep. It's the most natural form of self-care that we have."

As a result, not getting enough sleep can prevent the restorative processes that occur during sleep from happening, including muscle recovery, hormone regulation, immune functioning, and memory consolidation.

"During sleep, the immune system produces protective mechanism antibodies and cytokines which help combat infections from viruses, bacteria and other illnesses," said Fouzia Siddiqui, a neurologist and sleep center medical director at Sentara Health.

Not getting enough sleep can have a significant impact on your physical health and increase the risk of:

• Cardiovascular disease
• Heart attack
• Stroke
• Obesity
• Type 2 diabetes and insulin resistance
• Metabolic syndrome
• Weakened immune system

"Chronic sleep loss weakens the immune system and raises inflammation, which can make you more prone to infections," said Gunjan Narwani, a neurologist at Houston Methodist Clear Lake Hospital.

A lack of sleep can also impact your cognitive abilities. A 2023 study published in The Lancet found that people who get less than six hours of sleep a night and exercise at a high level had faster cognitive decline than those who slept the same amount but didn't work out as often. This suggests that those who exercised heavily were not sleeping enough to restore and rejuvenate their bodies.

A lack of sleep can also make you more likely to experience anxiety and depression, as well as issues staying alert, which is why sleep deprivation has been linked to an increased risk of car crashes. One 2018 study found that sleeping around six hours per night was associated with a 33% higher crash risk than those who slept seven to eight hours.

How much sleep do you need?

On average, most adults require between seven and nine hours of sleep each night, though according to CDC, almost 40% of Americans say they don't regularly hit that number.

"Contrary to popular belief, sleep is an extremely active process, rather than a perceived shutdown of the body, as the brain and body go through critical maintenance," said David Benavides, a board-certified sleep medicine physician at Harvard Medical School and Mass General Brigham.

How much sleep you need changes as you age. For example, newborns generally need between 14 and 17 hours of sleep.

"Definitely when we're babies and children, because we are growing so rapidly, we do need a lot more sleep," said Molly Atwood, a behavioral sleep medicine clinician at Johns Hopkins.

The National Sleep Foundation has recommendations for how much sleep each age group should get based on their needs:

How to improve the quality of your sleep

When trying to figure out how much sleep you need, it's important to also think about the quality of your sleep, Pelayo said. "What you really want to do is wake up feeling refreshed — that's what it's about."

"If somebody tells me that they sleep many hours but they wake up tired, something is wrong," Pelayo added. "You shouldn't leave your favorite restaurant feeling hungry."

Experts suggest several tips to help improve your sleep each night, including:

• Dedicating seven to nine hours for sleep
• Creating a consistent sleep schedule, including on weekends and holidays
• Developing a soothing pre-sleep wind-down ritual like listening to relaxing music, doing deep breathing exercises, or stretching
• Avoiding the use of phones, tablets, or watching TV within one hour of sleep
• Dimming the lights and potentially lowering the temperature in your room before sleep

If you're still struggling to sleep, Naik said you should talk to your primary care provider who may refer you to a sleep specialist.

A doctor will discuss your health and sleep history with you, including whether you snore or wake up with headaches, and rule out any underlying health issues that could be impacting your sleep. Naik said you could be recommended for a sleep study to get more information on your sleep issues and find the best treatment.