Higher BMI Linked to Less Sleep
A study from Walter Reed Medical Center shows that higher BMI is linked to getting less sleep. Not only is sleep quality important to maintain a healthy weight, but sleep duration is also important to keep weight stable. Results of a newer study show that people who sleep less have a higher body mass index (BMI).
Findings presented Sunday, May 17, 2009 at the American Thoracic Society's 105th International Conference in San Diego, show that fourteen nurse volunteers enrolled in the Integrative Cardiac Health Project at the Walter Reed Medical Center had higher BMI’s as the result of less sleep, compared to nurses who slept longer.
The researchers engaged the nurses in nutritional counseling sleep and stress management, and exercise training, analyzing total activity, body temperature, and body position; facilitated by use of an actigraphy armband. The study revealed that even increased activity did not equate to lower BMI for the nurses who slept less.
Lead investigator Arn Eliasson, M.D. says, "When we analyzed our data by splitting our subjects into 'short sleepers' and 'long sleepers,' we found that short sleepers tended to have a higher BMI, 28.3 kg/m2, compared to long sleepers, who had an average BMI of 24.5. Short sleepers also had lower sleep efficiency, experienced as greater difficulty getting to sleep and staying asleep."
Additionally, people who sleep less may be more stressed, leading them to eat more, thus accounting for the increased BMI associated with less sleep. "Higher perceived stress may erode sleep. Stress and being less rested may cause these individuals to be less organized than normal weight individuals, meaning they would have to make more trips and take more steps to accomplish the same tasks. This might add to their stress and encourage other unhealthy behaviors like stress eating," says Dr. Eliasson.
Other unhealthy behaviors might explain the exact link between higher BMI and increased weight in people who sleep less. The researchers are also planning studies to measure hormone levels. The authors speculate that less sleep may disrupt the balance of the hormone leptin that tells us when we have had enough to eat, leading to increased food consumption and higher BMI.