Lack of Sleep in Teens May Lead to Obesity

Sept. 14, 2022 – Like many parents of teens, LaToya S. worries about her son’s sleep habits. In the early weeks of the pandemic, when her then-13-year-old had no way to connect with friends, she dropped some of her typical rules about screen time. It didn’t take long before her son’s bedtime began creeping later and later, he began playing video games with friends until the wee hours, and quality overnight sleep went out the window. Two years later, LaToya is still working to restore him to normal sleep patterns.

There’s good reason for her efforts. The link between poor sleep habits and poor health are well-established. For teens, it can mean lower grades, higher rates of mood disorders, a higher risk of substance abuse, and more.

“When he went back to school after lockdowns, we began seeing the effects of his disrupted sleep patterns,” says LaToya. “The teachers were noticing that, after the first couple of hours, he was nodding off in class. He began falling behind, especially in classes that required extra effort. We recognized that we had to make changes.”

As if school performance isn’t enough to worry about, for parents like LaToya, a new study has added another area of concern: Too little sleep in teenagers is linked to obesity and being overweight.

The Supporting Data

The study, authored by Jesus Martinez Gomez, a researcher in training at the Cardiovascular Health and Imaging Laboratory at the Spanish National Centre for Cardiovascular Research, looked at the link between sleep duration and health in more than 1,200 adolescents, divided evenly between boys and girls. Researchers began measuring sleep at age 12, and then repeated the exercise again at 14 and 16 years of age. Each time, the people in the study wore activity trackers for 7 days.

Along with sleep measurements, the researchers measured body mass index (BMI) throughout the study. They also calculated a score of things that can raise the odds of heart disease and other conditions, ranging from negative (healthier) to positive (unhealthier) values. Also, researchers measured and tracked waist size, blood pressure, and blood glucose levels.

The American Academy of Sleep Medicine recommends that teens between the ages of 13 and 18 consistently sleep between 8 and 10 hours a night for optimal health. But the Spanish study found that at 12 years of age, only 34% of those in the study achieved a full 8 hours of sleep a night. When subjects reached 14, that number dropped to 23%, and at 16, it fell to 19%. Tying in the data for overweight and obesity, at 12 years old, 21% fell into that category; at 14, the number increased to 24%; and by 16, when sleep was at its lowest levels, the number rose to 27%.

Laura Sterni, MD, director of the Johns Hopkins Pediatric Sleep Center, isn’t surprised by these findings. “We are failing to make sure our teens get adequate sleep,” she says. “There are a number of contributing factors, and the detrimental impact is great.”

When it comes to the obesity link, the lack of sleep as a cause isn’t quite there yet, but it’s likely.

“Right now, it’s correlation, not causation, but parents should still consider the link,” says Bruce Bassi, MD, medical director and founder of TelepsychHealth, an online therapy provider. “All the effects that come with sleep deprivation are exactly the opposite of what you want. Sleep deprivation turns on the toddler sides of our brains – we become crankier and look for soothing, and sometimes that’s food.”

“We’re getting more data all the time,” Sterni says of finding that sleep deprivation leads to obesity. “The risk factors for obesity appear to be dose responsive.”

Indeed: As the Spanish study highlights, the less sleep a teen gets, the more likely they are to become overweight or obese.

“We know that insufficient sleep leads to alterations in important hormone control and metabolic markers,” Sterni says. “It impacts the hormones that make us feel full by lowering them, and conversely makes our hunger rise.”

Lack of sleep also impacts how a body metabolizes glucose, leads to insulin resistance, and makes eating poor carbohydrates more appealing to the body, explains Sterni.

“Then there’s the fact that when you’re up late, you’ve got greater opportunity to eat, maybe mindlessly snacking on bad foods while in front of screens,” she says. “You’re sleepy during the day, so you’re not as inclined to exercise, either. Lifestyle factors get woven into the picture.”

Today’s teens are notoriously busy, too, which doesn’t encourage steady, regular bedtime habits. Social activities, sports, and club and school commitments can all push bedtimes later and wake-up times earlier. Add it all up, and lack of sleep can set teens up for a lifetime of health issues, many due to unhealthy weight.

How to Help Your Teen

While the data can be sobering, there are important ways parents can help their teens develop better sleep habits.

“The good news is that there’s some data showing that if you teach families and young people about the importance of sleep, they will listen and work to preserve healthy sleep habits,” says Sterni. “It’s as important as brushing your teeth, and you should always work towards getting adequate amounts.”

Bassi says that one of the most logical places to begin is encouraging earlier bedtimes.

“For most teens, the end marker of sleep is fixed because of school, so focus instead on when they get to bed,” he suggests. “Encourage better sleep hygiene and reducing stimulation before bed.”

That means setting up good screen-time habits, one big piece of the approach that Greg F. and his partner have taken. Parents of a 15-year-old and 17-year-old, they set up hard and fast rules for their devices.

“They can only use their phones in the common areas of the house, and they must power them down at 8:45 at night,” Greg explains. “In the morning, they cannot use their phones until all their chores and breakfast are finished. We believe it’s best that they get sleep on both the front and back ends before they have phones in hand.”

Exercising during the day can also improve the odds that a teen will be ready for sleep at a reasonable hour in the evening. With both kids active in sports, that’s another box that Greg’s family is checking.

“Parents can also demonstrate their own good habits,” suggests Bassi. “Positively reinforce your guidelines by shutting down your own screens in the evening.”

Greg is heeding that advice.

“We don’t have a television in our bedrooms, we go to bed early, and we open a book before bed,” he says.

Napping is another area worth visiting. As many parents of teens know, this is an age group that likes to nap when they can.

“I’m not against napping,” says Sterni. But, he says, “limit naps to 45 minutes to an hour, and try to prevent your teen from napping too close to bedtime.”

While there are plenty of areas to work on with teens and sleep habits, Sterni recommends starting with one or two, instead of taking them on all on at once.

“You’re not going to accomplish them all right away,” she says. “Just work toward the goal of 8 hours on average, however you need to take it on.”

For LaToya, the work toward improving her son’s sleep habits is far from over, but she’s seeing progress. The family has set up shutdown hours on their router, established a 10 p.m. bedtime, and even given their son an old-fashioned alarm clock to replace his phone’s alarm in his room. As habits improve, they may revisit some of the rules.

“We’ve recognized that teens need incentives for positive behavior as much as younger children,” she says. “Our consistency is paying off, and we’re being patient with his progress.”

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