Lost sleep causes more than just bags under your eyes.
Getting enough sleep is a basic human need that all too often gets overlooked in the rush to squeeze more hours into the day. Ignoring that need, however, can lead to serious health consequences: Sleep deprivation jeopardizes your safety, ability to concentrate, mental stability, and long-term well-being.
"The more people look into it, the more they find significant health problems associated with a lack of sleep," said William Kohler, MD, medical director of the Florida Sleep Institute in Spring Hill, Fla. "You need to get the proper quantity and quality of sleep, and we need to pay attention to it like we pay attention to diet and exercise."
The mind and the body repair and refresh themselves during sleep. The mind uses sleep to consolidate memories and "reset" the brain for the coming day. The body needs sleep to release important hormones, perform needed repairs, increase blood flow to the muscles, and boost the immune system.
When a person misses one good night's sleep, all these functions falter. You might have trouble staying awake or paying close attention. You feel less energetic and are more likely to come down with a cold. Chronic sleep deprivation – consistently not receiving enough sleep – amplifies these problems and increases health risks because your body cannot replenish itself.
"You're building up a sleep debt. Every single night you're adding to that debt, and unless you pay down that debt on a regular basis, you will see an effect on your ability to think and to perform," said Christopher Drake, PhD, a sleep researcher at the Henry Ford Sleep Disorders Center and an associate professor of psychiatry and behavioral neurosciences at the Wayne State University School of Medicine in Detroit.
Emotional and Cognitive Effects
Chronic sleep deprivation has been shown to drastically affect a person's mood and anxiety level. You might feel angry and irritable or sad and depressed. You might find yourself acting impulsively or lacking motivation to do anything. A lack of sleep ramps up the part of the brain that contributes to excessive worrying, making a sleep-deprived person edgy and anxious. Sleep deprivation also has been linked to suicide and risk-taking behavior.
People dealing with acute sleep deprivation also have a hard time thinking. It becomes more and more difficult to learn new things or solve problems. Short-term memory suffers, and you become less able to plan, organize, or "think outside the box."
"That sleep loss will impact your ability to use your brain," Drake said. "That comes from a reduction in metabolism of the frontal portions of your brain -- what we call the 'executive' portions of the brain. All those cognitive effects are felt on a daily basis if you are living on less sleep than you need."
Perhaps the most serious health risk from sleep deprivation is also the most obvious: sleepiness itself. You're very likely to nod off when you haven't gotten enough sleep, sometimes with dire consequences. According to the National Highway Traffic Safety Administration, about 56,000 car crashes are attributed to driver fatigue each year, leading to 1,550 deaths and about 40,000 injuries. Sleep deficiency has also played a role in tragic accidents like nuclear reactor meltdowns, the grounding of large ships, and airplane crashes.
Chronic Health Risks
The cognitive effects of chronic sleep deprivation are obvious. The metabolic and physiological effects are much more insidious. By eroding the body's ability to replenish and repair itself, you make yourself vulnerable to chronic health risks including:
Obesity. Sleep deprivation plays havoc with the hormones that govern a person's hunger, causing night owls to overeat and indulge in fatty foods, becoming overweight. "The hormones leptin and ghrelin get dysregulated. We get less of the hormone that helps us feel satiated when we eat, and we get more of the 'hunger hormone,'" Drake said. "We are processing calories less efficiently, and we also tend to eat more than we need."
The effect of sleep deprivation on obesity is so strong that "you can predict which children will become obese in five years based on how much sleep they are getting," Dr. Kohler said.
Diabetes. A lack of sleep reduces the body's ability to process insulin. Fat cells suffer a 30 percent reduction in their ability to respond to insulin. "Our metabolism requires [that in order] for us to process glucose, we need to have that full seven to nine hours of sleep a night," Drake said. If unchecked, such insulin resistance can lead to chronically high blood sugar levels and ultimately diabetes.
Heart disease. Sleep deprivation can increase the amount of inflammation in the body. Such inflammation, when coupled with other health risks like obesity and diabetes, may increase a person's risk for heart disease.
Other health risks. Sleeplessness also has been linked to kidney disease, high blood pressure, and stroke. People are more keenly aware of pain and body discomfort after they've gone a couple of nights without good sleep. And don't forget the effect of sleep deprivation on the immune system. People who are sleep-deprived do not respond as well to vaccines, a clear indication that sleeplessness makes the body less able to fight off infectious disease.
Even your skin suffers. Poor sleepers show increased signs of skin aging, and their skin is less able to recover from stressors like sunburn. "There are clearly effects on how you look," Drake said. "One only needs to observe someone who's pulled an all-nighter."
Most mental and physical health risks are reversible if people return to a healthy sleep pattern. But that's a big if.
"We're a 24/7 society now, and we have a lot of sleep-deprived people these days," Kohler said. "We are a tired people, and we need to be educated on ways to improve our sleep habits."
By Dennis Thompson Jr.
Medically reviewed by Farrokh Sohrabi, MD
