Have you slept enough this week? When did you last wake up without an alarm clock and not need caffeine? If either of these questions is “no,” you’re not alone. In many developed countries, more than a third of adults don’t get enough sleep.
You may be surprised by the consequences, though. Sleeping less than six hours a night weakens your immune system, increasing cancer risk. Insufficient rest appears to increase Alzheimer’s risk. Inadequate sleeping, even for a week, can cause pre-diabetes. Short sleeping increases the risk of blocked and brittle coronary arteries, leading to cardiovascular disease, stroke, and heart failure. Sleep disruption contributes to all major psychiatric conditions, including depression, anxiety, and suicidality.
If you’re tired, do you eat more? No accident. Too little sleep boosts a hormone that makes you hungry and lowers another that signals fullness. You want more food despite being full. Insufficient sleep causes adults and children to gain weight. If you diet without enough rest, you’ll lose lean body mass, not fat.
“I’ll sleep when I’m dead” is bad advice
The shorter your sleep, relative to the recommended seven to nine hours, the shorter your lifespan. “I’ll sleep when I’m dead” is bad advice. Adopting this mindset could shorten your life and reduce its quality. Sleep deprivation has a breaking point. Humans are the only species that will intentionally go without sleeping. The Center for Disease Control declared insufficient sleep a public health epidemic. Countries where sleeping-time has declined most dramatically over the past century, like the US, UK, Japan, South Korea, and several in western Europe, also have the highest rates of physical diseases and mental disorders.
Scientists lobby doctors to “prescribe” sleep. It’s painless and enjoyable medical advice. This is not a call for doctors to prescribe more sleeping pills, given the evidence of their harmful health effects.
Could lack of sleep kill you?
Two times yes. First, a rare genetic disorder starts with midlife insomnia. The patient stops sleeping after several months. They’ve lost many brain and body functions by this point. Few drugs help patients rest. The patient will die after 12-18 months without sleeping.
Second is driving while sleepy. Drowsy driving causes tens of thousands of accidents and deaths annually. Not only is the sleep-deprived person’s life at risk, but so are others. Fatigue-related errors cause one traffic death per hour in the U.S.
Science has historically failed to explain why we need sleep, contributing to society’s apathy. Sleeping was a biological mystery. Genetics, molecular biology, and high-powered digital technology have failed to unlock sleep’s vault. Nobel Prize–winner Francis Crick, who deduced DNA’s twisted-ladder structure, Roman educator Quintilian, and even Sigmund Freud all tried to decipher sleeping’s enigmatic code in vain.
Doctors and scientists couldn’t explain why we sleep until recently. We’ve known the functions of the three other basic drives—to eat, to drink, and to reproduce—for decades, if not centuries. The fourth biological drive, sleep, has eluded science for millennia.