I stayed up late working the other night (no, not New Year's Eve) and didn't sleep enough. The next day I felt irritable and had trouble concentrating as a result. Can you relate? In some ways, sleep deprivation is a celebrated American ideal: we admire those who burn the "midnight oil" and "candle at both ends." But it's also a major public health problem that is rarely discussed.

The brain needs sleep to keep the body alive. Lab rats, for example, typically live for two to three years, but research has found that they survive a mere five weeks when deprived of REM sleep - and only three weeks when completely sleep-deprived. Humans are different than lab rats in many respects, but pretty similar when it comes to the importance of sleep.

Inadequate sleep, in quantity of hours or quality of depth, affects how well our bodies function and how good we feel. There is a strong association between poor sleep and depression, with about 90 percent of people diagnosed with the disorder reporting sleep problems. While it's not clear whether depression causes poor sleep or if poor sleep causes depression (it's probably a bit of both), new research is finding that effective sleep therapy can lead to reductions in depressive symptoms, suggesting that poor sleep might be the primary cause in some cases. An estimated 50 to 80 percent of people receiving mental health services have a chronic sleep problem, compared to 10 to 18 percent of adults in the general U.S. population.

Insufficient sleep is also associated with the dysregulation of neuroendocrine and metabolic systems, increasing risk for diabetes and obesity, as well as heart disease and high blood pressure.

So how much sleep does a person need to stay healthy? It depends, but sleep science has produced some general guidelines on the basis of age. Infants require about 16 hours daily while teenagers need nine and adults seven to eight. Deep sleep becomes harder to come by as you get  older; it's estimated that half of people over the age of 65 in the U.S. have sleep problems.

A lot don't sleep enough. As a result, sleep health was added as a category in Healthy People 2020, formally establishing it as a federal public health priority. Specific objectives include:

  • Connecting people who might have sleep apnea to medical care: only 25 percent of people with symptoms sought medical care in 2005-08. The disorder is associated with high blood pressure, heart attacks, stroke, obesity, and diabetes, but also manageable with treatment.

  • Preventing car accidents caused by drowsy driving: 37 percent of Americans admit to falling asleep at the wheel in the past year.

  • Increasing the proportion of high school students who get at least eight hours of sleep per night: only 31 percent did in 2009.

  • Increasing the proportion of adults who get sufficient sleep: 70 percent did in 2008.

Just  about everyone knows the importance of hygienic practices like hand-washing to prevent spreading germs. Similarly, sleep hygiene offers some simple things you can do to improve sleep quality. Here are a few:

  • Skip the night cap. While alcohol induces sleep in the short term, it has a stimulant effect that makes you wake up, or sleep less soundly, a few hours later as the booze wears off. The recommended window for not drinking is 4 to 6 hours before bed.

  • Exercise during the day, but not right before bed. Exercise generally helps you sleep better, but it can have the opposite effect and keep you awake if you do it within two hours of hitting the hay.

  • Make your sleeping quarters like a deep, dark cave. The less light, the quieter the environment, the better you'll sleep. Blinds and curtains that block out street light, eye masks, and earplugs can be pluses.

  • Don't work in bed. Teach your mind and body that your bed is where you go to rest, not engage in strenuous mental activities and entertain stressful thoughts.

Check out some more tips for yourself; it's time for me to get to bed.

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