Obesity and depression may be responsible for regular drowsiness and not just sleep deprivation, says a new study.
Over 30 percent of the general population experience EDS- Excessive Daytime Sleepiness occurring throughout the day.
Researchers at Pennsylvania State University conducted a new study using physiologic sleep data to identify the cause and investigate the mechanism behind EDS. At the beginning of the study, researchers measured self-reporting of EDS at baseline and again an average of 7.5 years later in 1,395 men and women.
The researchers also recorded sleep, physical and mental health problems and substance use and determined whether participants were being treated for physical and mental health conditions.
"Obesity and weight gain predicted who was going to have daytime sleepiness. Moreover, weight loss predicted who was going to stop experiencing daytime sleepiness, reinforcing the causal relationship," said Julio Fernandez-Mendoza, assistant professor of psychiatry at the Penn State College of Medicine in the US.
The association between body mass index and sleepiness was independent of sleep duration. Obese people may be tired during the day, no matter how much they sleep at night.
Obese people are likely to feel tired because fat cells in the abdomen produce immune compounds called cytokines that promote sleepiness.
The study found that people with depression had high incidence of EDS. Physiologic sleep disturbances, taking longer to fall asleep and walking in the middle of the night, explained their daytime drowsiness.
Feeling drowsy and tired during the day result in poor work productivity, increase errors and automobile accidents.
These findings could lead to more personalized sleep medicine for those with EDS, said the researchers.
The researchers published their findings in the journal Sleep.