It turns out that the age-old advice to get a good night’s sleep may have more to it in terms of health benefits than ever imagined.
Later Bedtime, More Weight Gain
Recent research has found that teenagers or young adults who go to bed late on weeknights are more likely to gain weight over time.
In a study of nearly 3,500 adolescents who were followed between 1994 and 2009 in the National Longitudinal Study of Adolescent Health, researchers looked at how bedtimes affected body mass index (BMI) over time.
The study authors found that a “later average bedtime during the workweek, in hours, from adolescence to adulthood was associated with an increase in BMI over time.” The researchers noted that consumption of fast food in particular seemed to be playing a role in the relationship between bedtimes and BMI.
This finding does not appear to be limited to teenagers and young adults. In another study, researchers found that late bedtimes, and therefore less nightly sleep, for four-year-old and five-year-old children resulted in a greater likelihood of obesity over time. Specifically, the researchers found that the odds of becoming obese were higher for children who slept less than about 9.5 hours per night, as well as for children who went to bed at 9:00 p.m. or later.
Health Benefits of Sleep
A plethora of studies in adults have reflected similar results. Most studies have shown that seven to nine hours of uninterrupted sleep per night are required to reap the health benefits of good sleep in adults, including those related to preventing obesity.
In addition to preventing obesity and overweight, getting enough high-quality sleep every night can help prevent heart disease, stroke, depression, and other chronic disorders. When we sleep, the body gets a chance to repair and restore itself. If it does not have enough time to do this over the long-term (chronically), then stress hormones and other inflammatory factors are released, as the body begins to react as if it were under chronic stress (which, without enough sleep, it is).
One of the main players in terms of stress hormones is cortisol, which is released in response to chronic stress.
Among many other of its influences on the body, cortisol causes glucose (sugar) to be released into the bloodstream so that it is more readily available to feed the brain. As an evolutionary response to chronic stress, this probably worked quite well, enabling a person under stress to respond with more brain power. However, in today’s world, an unwanted side effect of cortisol’s actions is the tendency for weight gain (makes sense that our ancestors would need to store or hold onto weight if they were truly under stress from a harsh environment). That weight gain, over time, can translate into obesity.
Indeed, studies have shown that lack of adequate sleep can result in overeating. And for those who are trying to lose weight, getting enough sleep (again, at least seven hours per night) increases the chance of success with weight loss.
For children, as shown by the studies described above, the amount of sleep needed is even greater, sometimes 10 or more hours per night, depending upon age.