Sleeping too little or even too much has been associated with several disease conditions including metabolic syndrome that predisposes a person to develop diabetes, stroke and heart disease. The findings of the study titled, “Association between sleep duration and metabolic syndrome: a cross-sectional study,” was published in the latest issue of the journal BMC Public Health.
For their study, a team of researchers from South Korea at the Seoul National University College of Medicine looked at the association between duration of sleep and metabolic syndrome. Metabolic syndrome is typically a combination of several conditions such as excessive fat around the waist, raised blood sugar, raised blood pressure and raised levels of triglycerides and cholesterol. The team of researchers obtained sleep as well as health parameters data from a large population of men and women from the Health Examinees (HEXA) study.
The study was conducted between 2004 and 2013 and looked into detailed medical histories, prescription medication use, exercise and diet levels and sleep durations of 133,608 Korean participants (44,930 men, 88,678 women) aged between 40 and 69 years. Blood and urine samples were collected from them for testing the biochemical parameters. Each of the participants were asked to detail the total number of hours they spent sleeping per day. This included night time sleep as well as day time naps.
They found that 29 and 24 percent of men and women respectively had metabolic syndrome. Additionally they saw that on an average, people who slept for less than six hours a day or more than ten hours a day were at a greater risk of metabolic syndrome than those who slept an average of six to seven hours a day. The researchers noted 11 percent of the sample of men slept for less than six hours and they were more likely to have a larger waist and metabolic syndrome. They noted that 13 percent of the women participants slept for less than six hours per day on an average and they were more likely to have a greater waist measurement. On the other hand 1.5 percent of the men slept for over ten hours per day and were at a greater risk of metabolic syndrome and higher triglycerides in their blood. Of the participants 1.7 percent women slept for more than ten hours per day and these women were at a greater risk of metabolic syndrome, larger waist circumference, raised blood sugar and triglycerides and lower levels of good cholesterol (HDL-C).
Lead author of the study Claire E. Kim from the Department of Preventive Medicine at Seoul National University College of Medicine, in her statement said, “We observed a potential gender difference between sleep duration and metabolic syndrome, with an association between metabolic syndrome and long sleep in women and metabolic syndrome and short sleep in men.” Kim said that this is the largest study that examines the “dose response” association between metabolic syndrome and sleep duration. She added that more research is necessary to find the exact reason how sleep is associated with metabolic syndrome. Researchers added that hormones could play a role in this association.