Lack of sleep linked to weight gain in teenagers

Teenagers who don't get enough sleep may be more prone to putting on weight, new research suggests.

US sleep experts surveyed 108 male and 147 female teenagers at a Texan high school. Participants were asked to record the amount of sleep they got during weekdays and at the weekend. They were also asked for their height and weight so that the researchers could calculate their body mass index (BMI).

On weekdays, male teenagers averaged six hours 32 minutes sleep and nine hours 10 minutes at weekends, while among females, the average amount of weekday sleep was six hours 30 minutes and the average amount of weekend sleep was nine hours 22 minutes.

The researchers found that male teenagers who slept less than seven hours on weekdays had a BMI that was 3.8 per cent higher than those who slept for longer.

Similarly, female teenagers, who slept less than seven hours on weekdays had a BMI that was 4.7 percent higher than those who got more than seven hours sleep.

The researchers, from the Baylor College of Medicine Sleep Center in Houston, Texas, also noted that obesity was linked to less than eight hours sleep a night in male teenagers, with the fewest hours slept linked to the highest BMI's.

"Sleep is food for the brain. When teens do not get enough sleep, they fall asleep in class, struggle to concentrate, look and feel stressed, get sick more often, and do not meet their obligations due to tiredness," said study author Lata Casturi.

"Teens who sleep fewer than eight hours may also consume more calories than those who sleep more than eight hours.

"Therefore, they have a higher risk for obesity and associated health problems, including high blood pressure, heart disease, and stroke."

The researchers believe the sex-related difference in sleep and weight gain may be due to the differences in body composition during puberty.

"Males and females experience differential growth rates and hormone secretion during puberty. The sleep factors that impact metabolism may increase weight gain differently in the two sexes," explained Ms. Casturi.

In addition to weight gain, lack of sleep during teenage years can result in poor sleep habits that continue into adulthood and result in long-term health problems.

Study co-author Anita Rao added: "Sleep promotes growth in children and adolescents and strengthens the immune and nervous systems.

"Hence, sleep deprivation early in life may cause the youngsters to suffer from a lifetime of irreversible higher health risks."

The study was presented at the annual meeting of the American College of Chest Physicians in Honolulu.

This article was published on Wed 26 October 2011