Teen obesity is a serious problem in the United States, with the Centers for Disease Control and Prevention reporting that 18 percent of adolescents were obese in 2008. Obesity is when excess fat accumulates on the body, putting extra stress on the joints and putting the vital organs in danger. This condition also increases the risk for diabetes, stroke, heart attack, high blood pressure and other serious problems. What many people do not know is that early school start times may be at least partially to blame for this significant increase in obesity among adolescents. Scientists know that there is a clear link between sleep deprivation and obesity, increasing the risk of obesity for adolescents who are forced to start school as early as 7:00 a.m.
The Sleep Deprivation-Obesity Link
The Nurses’ Health Study, a very large study involving 60,000 women, followed participants for 16 years. Study investigators asked each participant about her weight, sleep habits, nutrition and other lifestyle issues. When the study started, none of the participants were obese. At the conclusion of the study, researchers found that the women who slept five hours per night or less had a 15 percent higher risk of developing obesity when compared to women who got seven hours of sleep each night. Harvard School of Public Health suggests that sleep deprivation may contribute to obesity in several ways. One is that tired people may not have the energy to exercise, reducing the amount of calories they burn each day. Those who struggle with sleep deprivation may also eat more than other people, as they are awake for a longer period each day. Finally, the sleep cycle plays a role in regulating the hormones responsible for controlling appetite. People who do not get enough sleep may have an imbalance of these hormones, causing them to feel hungry and consume more calories than normal.
Lack of Sleep Multiplies Obesity Risk
Several research studies have confirmed the link between lack of sleep and obesity. One study, which appeared in the journal Pediatrics, followed 308 children from Louisville, Kentucky. Before the study started, the participants were classified as normal weight, overweight or obese. During the study, the children wore a wrist device to track their sleep patterns. The children who got the least amount of sleep were 4.2 times more likely to be obese than the other children in the study. Even those who slept extra on the weekends had a tripled risk of obesity. Dr. David Gozal, one of the lead investigators, says that adequate sleep may provide some protection for a child with a high risk of obesity. Early school start times make it difficult for teens to get adequate sleep, as evening activities and homework sessions keep kids up until 10:00 p.m. or later. Then they have to wake up at 5:00 or 6:00 a.m. to get ready for school.
Sleep is Just as Important as Diet
Dr. Amy Aronsky, a board-certified sleep specialist, says that “good sleep is as important as a good diet and exercise when it comes to weight loss.” When Americans averaged eight hours of sleep each night, the obesity rate for the United States was 12 percent. Now that Americans average 6.5 to seven hours of sleep each night, the obesity rate is approximately 30 percent. Aronsky suggests that altered hormone levels are to blame. Sleep deprivation increases the amount of grehlin in the body and decreases the amount of leptin in the body. Grehlin makes people feel hungry and leptin tells the brain when the stomach is full. High levels of grehlin and low levels of leptin make people feel hungry, even if they have eaten enough food. This may lead to the consumption of extra calories, increasing the risk for obesity.
Sleep Apnea Linked to Obesity
Sleep apnea is a serious medical condition that causes shallow breathing or brief interruptions in breathing during sleep. The pauses can occur as many as 30 times per hour, according to the National Heart Lung and Blood Institute. Shallow breathing and interrupted breathing both disrupt the sleep, as people with sleep apnea move from deep sleep to light sleep when these breathing changes occur. This leads to daytime sleepiness, fatigue, headaches and other complications. Sleep apnea has also been linked to three conditions that play a role in the development obesity. People with sleep apnea have an increased risk of insulin resistance and tend to have more sedentary lifestyles than people without sleep apnea. Additionally, sleep apnea seems to speed up the progression of liver disease.
Johns Hopkins University researchers found that sleep-disordered breathing has a strong link to insulin resistance, which is the body’s inability to break down glucose (blood sugar). This increases the risk for type 2 diabetes in adolescents and adults. Another study from Johns Hopkins showed that sleep apnea patients tend to have liver problems in direct proportion to the severity of their sleep disorder. Dr. Vsevolod Polotsky hypothesizes that hypoxic stress caused by shallow or interrupted breathing may cause oxidative stress in the livers of obese patients. This leads to additional inflammation, causing the liver problem to progress rapidly.
Examining Sleep Patterns
Parents and adolescents should sit down and examine their sleep patterns. Adolescents should be getting a minimum of eight hours of sleep each night, with some teens needing as much as ten hours of sleep per night. Parents should ask their teens if they wake up feeling rested or if they wake up feeling tired and lethargic. Make note if your teen reports waking up frequently during the night or any other sleep disturbances. If you notice any abnormal patterns, report them to your family physician. The physician may recommend lifestyle changes or, if the sleep problem is significant, suggest that your teen participate in a sleep study.