When you're habitually sleep deprived -- more than just one night when we can't sleep a wink -- you're actually hurting yourself. Too little or poor quality sleep disrupts your body's biological rhythms, and it doesn't take long to hurt your physical, emotional and mental health. It stresses not only the body but also your relationships, your work and the other activities in your life. And it doesn't take long -- if you lose 90 minutes of sleep tonight, for instance, you'll find yourself as much as 32 percent less alert tomorrow [source: Breus]. If you're going to lose sleep over something, let that be it.
Being sleep deprived for even just one night leaves you more than tired; it shortchanges you at the sleep bank. Withdraw too much without depositing back some quality nights of dozing and you've got what's called a sleep debt. Add that up after a few days and you begin to see some negative consequences happening to your body. After just seven days, your circadian rhythm -- the body's 24-hour cycle, also known as the body's master clock that regulates your sleep-wake pattern as well as the release of hormones, body temperature, mood and other physical, cognitive and behavioral patterns) -- gets disrupted. Basically, that means that when you're running on a sleep deficit your body no longer keeps the correct time; it's as though your watch battery is running low and you're chronically arriving late. Your motor skills become impaired and your hormone levels rise or fall inappropriately (which can impact everything from how well your pancreas works to how fast you show your real age to how strong your sex drive is). You know how tired you are when you're suffering from jet lag? That's a disruption in your circadian rhythm.
Sleep deprivation changes how your body handles what's called its genetic expression. That means your genes, when you're fatigued, are not as efficient at giving out instructions as they normally would be. And without good instructions, your body's everyday processes begin to run inefficiently. Your immune system becomes compromised; you get sick more often. And not only with colds and flu, although yes, you will be sick more often if you're sleep deprived. Long-term sleep deprivation is associated with serious and chronic illness, including hypertension (high blood pressure), heart failure, stroke, metabolic syndrome and type 2 diabetes -- and the list goes on. The sleep-deprived also risk developing or worsening a mood disorder (and the greater the sleep debt, the greater the psychosis), becoming obese (not only does it impair how we handle insulin, but people who sleep only four hours a night eat more calories during the day) and dying prematurely (sorry, chronic insomniacs, your sleep deprivation causes you to die at a rate two times faster than that of people with a more normal sleep pattern).