As research linking sleep deprivation to excess weight grows, CU Anschutz experts promote behavioral interventions with a focus on back-to-school teens
Seven out of 10 teens trying to adapt to a fall schedule right now are missing out on sleep. Early bells and tough classes combine with delayed biological clocks during adolescence, keeping their nightly sleep time during the school year under the recommended 8-10 hours for their age group.
While most parents worry about (and lose sleep over) their teens' moods and grades, newer research suggests sleep deprivation can affect another U.S. health concern: the obesity crisis.
"It (sleep) is still emerging as that third pillar of healthy lifestyle, but I think people are increasingly recognizing that sleep is also an important aspect of weight management," said Stacey L. Simon, PhD, a sleep expert and professor of pediatrics at the University of Colorado Anschutz School of Medicine.
What does research reveal about sleep and weight?
Repeated studies in adults have shown that restricting volunteers' sleep leads to their consuming between 200 and 300 extra calories, said Seth Creasy, PhD, an associate professor of endocrinology, metabolism and diabetes.
Simon and Creasy, who is an obesity medicine researcher at the CU Anschutz Health and Wellness Center and the Colorado Nutrition Obesity Research Center on campus, were part of a study published this year reviewing sleep as a behavioral treatment for obesity.
"So diet and physical activity are still the two main drivers of weight gain from a behavioral standpoint, but sleep can help support both of those," Creasy said.
The early bell's toll: Poor sleep raises risk across the lifespan
Simon's research focuses largely on sleep in adolescents, whose circadian rhythms prevent them from falling asleep early, prompting the call for later school start times. Despite the American Academy of Pediatrics recommendation in 2014 that middle and high schools begin no earlier than 8:30 a.m., compliance lags, Simon said.
"A majority of schools start much earlier than that. Certainly, what we see in our sleep clinic at Children's (Hospital Colorado) is that, during the school year, teens are forced to sleep outside of their biological clock."
Given the toll the obesity crisis has on people's health and the country's healthcare system, Creasy and Simon hope their research will help support behavioral intervention in homes and healthcare for all ages.
Did you know? In the United States, nearly three-quarters of adults meet criteria for overweight and over 40% of adults and 22% of teens meet criteria for obesity.
"We're really seeing this across the lifespan: that individuals with short sleep duration are at increased risk for higher body weight," Simon said. Excess weight contributes to increased rates of type 2 diabetes, cardiovascular disease, some types of cancers, musculoskeletal diseases and premature mortality.
The cardiometabolic health consequences of the delayed sleep timing in teens is a chief concern for Simon. "We've seen that in adolescents short sleep duration and late timing of sleep are associated with poorer insulin sensitivity, that could over time increase risk for obesity and type 2 diabetes."
What is keeping teens from sleeping well?
An estimated 70% of high schoolers and 30% of adults don't get their recommended amount of sleep. The substantial lack of sleep in teens is particularly notable because of their unique developmental period, Simon said.
- Teens have a natural delay in circadian rhythm working against them: "Their brains are just programmed to not feel sleepy until very late."
- In a recent sleep study by Simon and colleagues, parents and teens noted high anxiety levels, busy schedules and heavy use of electronic devices adding to their stress and lack of sleep.
- Teens have more autonomy when it comes to important behaviors, like what types of foods they eat and when and how often they eat, sleep and exercise.
"So it's sort of this confluence of factors that all increases risk for higher weight gain. And, unfortunately, we know that those behaviors that are set even in adolescence can be enduring into adulthood," Simon said.
Although the research still lags, some early evidence suggests females might draw an even shorter stick when it comes to the sleep/weight-gain issue.
"Our research found that adolescent females actually had earlier circadian timing compared to males, which may suggest an even greater sleep need," Simon said. And yet, females report higher levels of insomnia, she said. "So they may need more sleep, but they're actually getting less."
No longer "adult-onset" diabetes: Today's youth are experiencing higher rates of type 2 diabetes than ever before, and the disease is more aggressive in youth, leading to deadly symptoms earlier.
Why would sleep deprivation affect calorie consumption?
People actually consume more energy tossing and turning or staying up with insomnia, so the energy balance equation in itself cannot explain weight gain. "They may be overcompensating for those burned calories," Simon said.
Studies have linked shorter sleep duration with an increase in the hunger hormones leptin and ghrelin. "So they are getting those cues to feel hungry, and they're feeling less satisfied after consuming food. So that again could lead to overconsumption," Simon said.
"And there's been some really interesting research done looking at the reward system in the brain and how it's impacted by short sleep," she said. "It seems like when we aren't getting enough sleep at night, then it's almost like our brain is searching for some reward." Often, food - especially the high-sugar, high-fat variety - is the most available prize.
On the intervention side, researchers looked at people who routinely slept less than about six hours a night and extended their sleep each night for two weeks, Creasy said. "These people started getting closer to the recommended amounts, about seven and a half hours of sleep," he said. "And just naturally, those people started eating less by 270 calories per day."
See more articles in our CU Anschutz Newsroom Sleep Series.
How might inadequate sleep affect physical activity?
It is harder to study how lack of sleep can affect calories burned the next day, so fewer studies exist on the energy expenditure side, Creasy said. However, it makes sense that simply being tired after a bad night's sleep could increase sedentary behavior, he said.
Creasy was involved in one study where researchers restricted sleep for a group of New York City residents and then monitored their activity in their free-living environment, he said. "These people didn't use a car. So it was safe for them to be sleep-restricted for six weeks."
The results: "They were more sedentary. They ended up actually sitting more across the day, even adjusting for the amount of time that they were awake."
Simon's team has done studies with regularly sleep-deprived teens on school nights where the researchers orchestrate a schedule that allows for at least one extra hour of time in bed per night for the teens.
"And what we found was, not only were they successful at getting extra sleep during that study period, but they also had a decrease in their sedentary behavior time. And so it was almost like that hour or so before bed that they were otherwise on their phones or engaged in some of those sedentary behaviors, when we intervened, they just replaced that time with sleep."
Tips for Teens for Better Sleep
Stacey Simon, PhD, a sleep researcher and behavioral expert who counsels parents and teens at the Children's Hospital Colorado sleep clinic, offers advice on getting back into a sleep routine as the fall season gets serious after the Labor Day weekend.
- Give everyone (parents, teens, siblings, yourself) some grace. It is an adjustment period. It is really hard to transition from that summer schedule to a fall routine. There's also school stress, anxiety and new social situations that can impact sleep.
- Do your best to stick to that regular sleep schedule, including on weekends as much as possible. Sleeping in and staying up late on Fridays and Saturdays sets your progress back. It's called social jet lag, and it's like returning from a trip to New York every Monday.
- Avoid after-school naps. As exhausted as you feel, naps make it harder to fall asleep at bedtime.
- Try to have a bedtime routine of some kind. Do some pre-bed, wind-down activities as a buffer between your busy day and trying to fall asleep: reading, listening to music, journaling, drawing, whatever it might be.
- Avoid electronics before bed.
Key points:
- Insufficient sleep may contribute to weight gain by affecting both calorie intake and physical activity.
- Sleep-restriction studies have found that adults eat 200-300 more calories the day following a shortened night of sleep.
- Adolescents face particular sleep challenges because of delayed biological clocks and common social behavioral issues.
- Short sleep may affect hunger signals, food-reward responses, insulin sensitivity and sedentary behavior.
- Sleep should complement healthy eating and physical activity as part of weight management.
