“Because we found that adults who reported sleeping less than their peers were more likely to be overweight or obese, our findings highlight the importance of getting enough sleep,” said the study’s senior investigator, Laura Hardie, of the University of Leeds in England.
“How much sleep we need differs between people, but the current consensus is that seven to nine hours is best for most adults,” Hardie said in a university news release.
For the study, the research team looked at more than 1,600 adults in the United Kingdom. The participants reported how long they slept and kept records of what they ate. The participants also had blood samples taken and their weight, waist circumference and blood pressure measured.
The waists of those who slept an average of six hours a night were more than an inch larger than those who slept nine hours a night, the finding showed.
People who got less sleep also weighed more, and had reduced levels of HDL “good” cholesterol in their blood, which can cause health problems, according to the study authors.
However, the researchers found no link between shortened sleep and a less healthy diet.
The results were published online July 27 in the journal PLOS One.
According to study co-author Greg Potter, “The number of people with obesity worldwide has more than doubled since 1980. Obesity contributes to the development of many diseases, most notably type 2 diabetes. Understanding why people gain weight has crucial implications for public health.”
The study can’t show a direct cause-and-effect relationship between less sleep and weight gain. Still, the findings add to the growing body of evidence about the link between sleep and health, the researchers said.