Lack of sleep puts people at greater risk of obesity and diabetes, a new study published in the journal Science Translational Medicine confirmed. Sporadic and irregular sleep may cause a decreased metabolic rate, which could contribute to weight gain and a myriad of long-term health problems.
Researchers at Brigham and Women's Hospital in Boston found that disrupted sleep patterns raised blood sugar levels and slowed the body's metabolic rate, or the rate at which the body burns calories while at rest.
While several studies have analyzed sleep patterns in humans through observational epidemiological studies, this is the first to examine sleep behaviors in a completely controlled laboratory environment by mimicking jet lag and typical shift work sleep hours over a significant period of time.
"These findings are a substantial step forward from past work," said Orfeu M. Buxton, neuroscientist and lead study author. "We observed a new mechanism by which disrupted circadian (24-hour) rhythms can increase diabetes risk. Also somewhat surprisingly, these effects occurred in both young and older adults, and men and women."
The study included 21 health people who underwent sleep cycle tests for six weeks. Not only did researchers control how many hours of sleep each participant had, but they also controlled when they slept and other lifestyle factors, including activities and diet. Researchers varied the participants' sleep patterns. After a period of optimal sleep, or 10 hours, study participants then only slept about 6 during a 24-hour period. The sleep was sporadic throughout the cycle and intended to mimic a rotating shift work pattern. Participants ended the study with nine nights of recovery sleep.
Past studies have shown that shift workers are at higher risk of obesity and diabetes because of their disjointed sleep patterns and poor eating habits.
In the study, researchers found that the pancreas insulin response to a meal was lower in people who had not slept properly. Because of the slowed response, glucose levels rose higher and for longer after a meal, slowing the resting metabolic rate.
In other words, blood sugar went up and metabolic rate went down, putting people at greater risk of obesity and diabetes.
"Since night workers often have a hard time sleeping during the day, they can face both circadian (24-hour cycle) disruption working at night and insufficient sleep during the day," said Buxton. "The evidence is clear that getting enough sleep is important for health, and that sleep should be at night for best effect."
Michael Grandner, a research associate at UPenn's Center for Sleep and Circadian Neurobiology, said the was "great" in the way it showed how the "combination of sleep deprivation and misalignment with your internal clock takes a toll on the body in ways that neither one of those alone can cause."
"It shows that the combination is more than just a sum of its parts," he added.
Up to 40 percent of Americans experience insufficient during any given month, according to CDC research. Chronic sleep problems, like insomnia and sleep breathing problems, are common and have been shown to be associated with heart attacks, stroke, diabetes and obesity.
When patients are treated, these risks are dramatically reduced, said Grandner. Getting a diagnosis and treatment is key to overall health.
"We live in a society that brags about how little sleep we get by on," said Grandner. "When we hear someone brag about eating a whole pizza in one sitting, we know that was unhealthy and a bad idea. But when we hear someone brag about getting only a few hours of sleep, we don't have the same reaction, but maybe we should. We need to make sleep a priority for our health."