Korean researchers found that people who get less than six hours of sleep are more likely to exude risk factors for strokes, heart disease and diabetes.
Long-term lack of sleep is becoming more typical in industrialized communities. As per results of recent researches, chronic sleep deprivation is linked with poor health.
The authors of the new study said that the total amount of sleep may have an impact in the occurrence of metabolic disturbances; however, prospective studies that tackle the possible value of sleep in identifying high-risk individuals are not sufficient. In this study, the researchers investigated the relationship of full sleep duration and the development of metabolic syndrome in the long-term.
The population-based study involved 2,597 participants aged 40 to 70 years old. The subjects, who all had no metabolic syndrome at the beginning of the study, underwent a baseline check from 2005 to 2008 and a follow-up examination from 2008 to 2011. The participants were classified depending on the total duration of sleep that they reported in a questionnaire. Categories for the sleep duration include less than six hours, from six to 7.9 hours, eight to 8.9 hours and greater than or equal to 10 hours.
Metabolic syndrome was identified based on the recent combined definition.
The findings of the study showed that 558 or 21.6 percent of the participants developed metabolic syndrome after an average of 2.6 years of follow-up. Study subjects with less than six hours of sleep per night were found to have a 41 percent more chance of developing metabolic syndrome compared to those who slept for six to eight hours.
Sleeping for short durations was associated with approximately 30 percent increased risk of having elevated blood sugar and high waist circumference. People with lesser sleep was also found to have a 56 percent more chance of developing hypertension compared to those whose sleep duration was longer.
"Short sleep duration is an independent risk factor for incident metabolic syndrome in a population-based longitudinal study," the authors wrote.
"The 'short' sleepers should be aware of the risks of developing metabolic syndrome, which could lead them to suffer from life threatening and chronic diseases," said Dr. Jang Young Kim, the lead author of the study from South Korea's Yonsei University.
A study limitation that the authors acknowledged is the dependability on the subjects to correctly recall and report their medical states, sleep habits and lifestyle. The study was also observed to have lacking data on sleep quality.
Despite the identified limitation, Kristen Knutson, a sleep researcher from the University of Chicago, said that the results of the study are consistent with other investigations that have discovered a relationship between sleep duration, heart disease and metabolic syndrome. Knutson was not part of the study.
Knutson said that the possibility of reversing the effects of short sleep duration has not yet been confirmed. Through it all, she recommended that having a healthy lifestyle, including adequate sleep, proper diet and enough physical activity will be beneficial for health.
The study was published online in the journal Sleep Medicine on Sept. 25.
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