Optimal Sleep Duration in the Subarctic with Respect to Obesity Risk Is 8–9 Hours

• Main Authors: May Trude Johnsen, Rolf Wynn, Trond Bratlid
• Format: Article in Journal/Newspaper
• Language: unknown
• Subjects: Arctic; Norway; Tromsø; Northern Norway; Subarctic
• Online Access: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0056756; https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0056756&type=printable

Introduction: Sleep duration, chronotype and social jetlag have been associated with body mass index (BMI) and abdominal obesity. The optimal sleep duration regarding BMI has previously been found to be 7–8 hours, but these studies have not been carried out in the subarctic or have lacked some central variables. The aims of our study were to examine the associations between sleep variables and body composition for people living in the subarctic, taking a range of variables into consideration, including lifestyle variables, health variables and biological factors. Methods: The cross sectional population Tromsø Study was conducted in northern Norway, above the Arctic Circle. 6413 persons aged 30–65 years completed questionnaires including self-reported sleep times, lifestyle and health. They also measured height, weight, waist and hip circumference, and biological factors (non-fasting serum level of cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides and glucose). The study period was from 1 October 2007 to 19 December 2008. Results: The optimal sleep length regarding BMI and waist circumference was found to be 8–9 hours. Short sleepers (