Diets high in fat and sugar may not be the only contributors to childhood obesity. Researchers at the University of Michigan Center for Human Growth and Development followed nearly 800 students in grades three through six and found that elementary schoolchildren who got 9.25 hours of sleep per night had an obesity rate of 12.5 percent while those who slept fewer than 8.5 hours per night were almost twice as likely to be obese—23 percent. Their study, which was published in the November 2007 issue of Pediatrics, suggests three likely reasons the lack of sleep affects weight:
• Tired children might be less likely to be active and exercise during the day.
• Tired, irritable children might be more likely to consume junk food to regulate their moods.
• A possible connection exists between sleep and metabolizing fat.
The study was supported by the American Heart Association Fellow-to-Faculty Transition Award and the American Heart Association Midwest Affiliate Grant-in-Aid. Parents were interviewed about their children’s sleep habits at the start of the study when children were in third grade and again when they were in grade six. To determine the rate of obesity, researchers also measured height and weight of the children. Obesity was defined as having a body mass index higher than the top 5 percent of children for their age, height and weight. Eighteen percent of children in the study were obese by this measure by the sixth grade. Researchers took into account demographic data, such as maternal education, race and quality of home environment and parenting skills, to see if they had bearing on obesity. Regardless of demographics, too little sleep had the most significant correlation.
The University of Michigan obesity study appears to reinforce other studies showing that elementary schoolchildren need at least 10 hours of sleep per night to achieve optimal school performance.
The National Sleep Foundation (www.sleepfoundation.org) offers the following tips to help schoolchildren and parents get a good night’s sleep:
Tips for Children
• Keep a regular sleep schedule and avoid extremes on weekends.
• Establish a relaxing bedtime routine. Reading before bed is a good choice for children of all ages and for parents.
• Create a sleep environment that is cool, quiet, dimly lit and comfortable.
• Keep television, video games and other electronics out of the bedroom.
• Eliminate exposure to electronic media—television, video and computer games etc.— within an hour of bedtime. Studies show looking into bright lights, such as TV and computer screens, an hour or less before bedtime makes it difficult to fall asleep.
• Limit caffeine, especially after lunch.
• Eat well and exercise.
Tips for Parents
• Be an example by practicing good sleep habits.
• Talk to your children about the importance of healthy sleep and the consequences of sleepiness, including drowsy driving.
• Recognize that children, including teens, need more sleep than adults.
• Children who have difficulty waking in the morning on more than three days a week or who snore might not be getting adequate sleep and should be evaluated by a specialist.
• Establish a one-hour, electronic-free time before bedtime.
• Ask teachers whether your child is alert or sleepy during class and take steps to improve your child’s sleep if you feel that he or she may have a sleep problem.