Study links women’s waistlines with sleep habits

Swedish researchers have further proof that your sleep habits contribute to obesity. They found women who sleep less tended to have bigger bellies and waistlines.

Past studies have linked short sleep duration to higher body mass index (BMI) scores. In a study published in the May 1st issue of SLEEP, researchers wanted to learn the relationship between sleep length and quality and central obesity, a key risk factor associated with heart disease, diabetes and mortality.

Central obesity is measured by combining a person’s waist circumference with belly size.

The study took place in two phases. First more than 7,000 randomly selected women in Uppsala, Sweden answered questionnaires about their sleep disorders.

Researchers then randomly picked 400 of those women to take tests and answered another questionnaire about their lifestyle. More than half of those women were snorers.

Each subject underwent an extensive overnight sleep study in their own homes. They were free to choose when they would go to sleep and wake up. Researchers measured the women’s total sleep and length of time spent in REM and short wave sleep. They also assessed their sleep for episodes of sleep apnea.

The following morning, a nurse measured their waist circumference, sagittal abdominal diameter and BMI.

The researchers found centrally obese women were less active and had higher BMI scores. They slept less overall. The centrally obese women had less slow wave sleep and REM sleep.

The study noted the link between sleep and central obesity was stronger in younger people.

While these findings are further evidence there is a relationship between short sleep and obesity, the study has its limitations. It did not account for external factors like emotional stress.

Because researchers examined an existing population of centrally obese women, they could not pin down a causal relationship.

Read more about sleep and obesity on the Sleep Education blog.