Lack of sleep tied to teen sports injuries

For the abstract, "Lack of Sleep is Associated with Increased Risk of Injury in Adolescent Athletes," researchers asked middle and high school athletes (grades 7 to 12) enrolled at the Harvard-Westlake School in Studio City, Calif., to answer questions about the number of sports they played and the time they committed to athletics (at school and through other programs), whether they used a private coach, whether they participated in strength training, how much sleep they got on average each night, and how much they subjectively enjoyed their athletic participation. Seventy percent of the student athletes (112 out of 160 students; 54 males and 58 females; mean age 15) completed the survey, conducted in conjunction with Children's Hospital Los Angeles. Researchers then reviewed those students' school records pertaining to reported athletic injuries.

Hours of sleep per night was significantly associated with a decreased likelihood of injury, according to the study results. In addition, the higher the grade level of the athlete, the greater the likelihood of injury -- 2.3 times greater for each additional grade in school. Gender, weeks of participating in sports per year, hours of participation per week, number of sports, strength training, private coaching and subjective assessments of "having fun in sports" were not significantly associated with injury.

"While other studies have shown that lack of sleep can affect cognitive skills and fine motor skills, nobody has really looked at this subject in terms of the adolescent athletic population," said study author Matthew Milewski, MD.

"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," said Dr. Milewski. Instead, "what we found is that the two most important facts were hours of sleep and grade in school."

The advanced age risk may reflect a cumulative risk for injury after playing three or four years at the high school level, Milewski said, and older athletes are bigger, faster and stronger.