Tired teens may be putting themselves at risk for injury when they play sports, a new study suggests.

Researchers from the Children's Hospital of Los Angeles and the Institute for Scholastic Sport Science and Medicine found that teens who got at least eight hours of sleep a night or more had a lower risk of getting injured while playing sports than their sleepier counterparts.

The study included 160 student athletes with an average age of 15 (about half were boys, half were girls) who attended Harvard-Westlake School in California. Of those students, 112 participated in the questionnaire, which included questions about how many hours of sleep they got a night, how committed they were to athletics, whether strength training was part of their regimens, whether they liked playing sports and how many sports they played.

Researchers found that the teen athletes who got at least eight hours of sleep had a 68 percent lower risk of injury than those who got fewer hours. And the higher the grade of the student, the more likely he or she would suffer an injury -- with each advancing grade, injury risk went up by 2.3 times.

"When we started this study, we thought the amount of sports played, year-round play, and increased specialization in sports would be much more important for injury risk," study researcher Dr. Matthew Milewski, M.D., said in a statement. But "what we found is that the two most important facts were hours of sleep and grade in school."

The findings were presented at the national meeting of the American Academy of Pediatrics. Because the study has not yet been published in a peer-reviewed journal, its findings should be regarded as preliminary.

The National Sleep Foundation recommends that teens get more than nine hours of sleep per night (though some may only need closer to eight-and-a-half).

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    If you keep coming down with the sniffles -- or can't seem to kick that never-ending case -- you might want to assess your sleep schedule. A 2009 study found that people who sleep fewer than seven hours each night have almost <a href="http://articles.latimes.com/2009/jan/17/science/sci-sleep17">three times the risk of catching a cold</a> than people who slept for at least eight hours, the <em>LA Times</em> reported.

  • You're Clumsier Than Usual

    First you knock the alarm clock off the dresser, then you spill the milk as you're pouring your cereal, then you stub your toe on the way out the door -- you've become a klutz overnight. Researchers don't know exactly why, but sleepy people seem to <a href="http://www.prevention.com/amisleepdeprived/list/5.shtml">"have slower and less precise motor skills,"</a> Clete Kushida, M.D., Ph.D., director of Stanford University Center for Human Sleep Research told <em>Prevention</em>. Reflexes are dulled, balance and depth perception can be a little wonky and since you may also have trouble focusing, reaction time can be slowed, meaning you can't quite catch the egg carton before it hits the floor.

  • You've Lost That Lovin' Feeling

    If you or your partner just can't get in the mood, and stress or an underlying health problem isn't to blame, you might want to spend some extra time between the sheets -- sleeping. Both men and women who don't get their 40 winks experience a <a href="http://www.webmd.com/sleep-disorders/excessive-sleepiness-10/10-results-sleep-loss">decreased sex drive</a> and less interest in doing the deed, WebMD reports. A lack of sleep can also <a href="http://www.everydayhealth.com/erectile-dysfunction/causes-of-low-libido.aspx">elevate levels of cortisol</a>, the stress hormone, according to Everyday Health, which doesn't help in the bedroom either.

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