Losing 30 minutes of sleep per day may promote weight gain and adversely affect blood sugar control

Losing as little as 30 minutes of sleep per day on weekdays can have long-term consequences for body weight and metabolism, a new study finds. The results will be presented Thursday, March 5, at ENDO 2015, the annual meeting of the Endocrine Society in San Diego.

"While previous studies have shown that short sleep duration is associated with obesity and diabetes, we found that as little as 30 minutes a day sleep debt can have significant effects on obesity and insulin resistance at follow up," said lead study author Professor Shahrad Taheri, MBBS, PhD, professor of medicine at Weill Cornell Medical College in Qatar, in Doha. "This reinforces earlier observations that sleep loss is additive and can have metabolic consequences."
Because of social and work commitments, people often accumulate sleep debt during weekdays and make up for lost sleep over the weekend. But weekday sleep debt may lead to long-term metabolic disruption, which may promote the onset of, or exacerbate the progression of, type 2 diabetes mellitus.
"Sleep loss is widespread in modern society, but only in the last decade have we realized its metabolic consequences," Taheri said. "Our findings suggest that avoiding sleep debt could have positive benefits for waistlines and metabolism and that incorporating sleep into lifestyle interventions for weight loss and diabetes might improve their success."
Professor Taheri and his colleagues recruited 522 patients with newly diagnosed type 2 diabetes mellitus in the Early Activity in Diabetes trial and randomized them into one of three groups: usual care, physical activity intervention, or diet and physical activity intervention.
Participants completed 7-day sleep diaries and calculated their weekday sleep debt. At baseline, the researchers recorded their height and weight to determine obesity status, measured their waist circumference for central adiposity, and analyzed their fasting blood samples for insulin sensitivity.
At baseline, compared with participants who had no weekday sleep debt, those who had weekday sleep debt were 72% more likely to be obese, and by the 6-month mark, weekday sleep debt was significantly associated with obesity and insulin resistance.
At 12 months, for every 30 minutes of weekday sleep debt at baseline, the risk of obesity and insulin resistance was significantly increased by 17% and 39%, respectively.
The authors advise that future interventions designed to slow progression or reverse metabolic disease should consider all factors -- including sleep -- that affect metabolic function. Looking toward future research, they recommend that consistent optimum sleep hygiene and education may be a key component of successful future trials in metabolic disease control.
Diabetes UK and UK National Institute of Health research funded this study.

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Story Source:
The above story is based on materials provided by Endocrine Society. Note: Materials may be edited for content and length.

Light-emitting e-readers before bedtime can adversely impact sleep | sci-english.blogspot.com

Use of a light-emitting electronic device (LE-eBook) in the hours before bedtime can adversely impact overall health, alertness, and the circadian clock which synchronizes the daily rhythm of sleep to external environmental time cues | sci-english.blogspot.com

Use of a light-emitting electronic device (LE-eBook) in the hours before bedtime can adversely impact overall health, alertness, and the circadian clock which synchronizes the daily rhythm of sleep to external environmental time cues, according to researchers at Brigham and Women's Hospital (BWH) who compared the biological effects of reading an LE-eBook compared to a printed book. These findings of the study are published in the Proceedings of the National Academy of Sciences on December 22, 2014.

"We found the body's natural circadian rhythms were interrupted by the short-wavelength enriched light, otherwise known as blue light, from these electronic devices," said Anne-Marie Chang, PhD, corresponding author, and associate neuroscientist in BWH's Division of Sleep and Circadian Disorders. "Participants reading an LE-eBook took longer to fall asleep and had reduced evening sleepiness, reduced melatonin secretion, later timing of their circadian clock and reduced next-morning alertness than when reading a printed book."
Previous research has shown that blue light suppresses melatonin, impacts the circadian clock and increase alertness, but little was known about the effects of this popular technology on sleep. The use of light emitting devices immediately before bedtime is a concern because of the extremely powerful effect that light has on the body's natural sleep/wake pattern, and may thereby play a role in perpetuating sleep deficiency.
During the two-week inpatient study, twelve participants read LE-e-Books on an iPad for four hours before bedtime each night for five consecutive nights. This was repeated with printed books. The order was randomized with some reading the iPad first and others reading the printed book first. Participants reading on the iPad took longer to fall asleep, were less sleepy in the evening, and spent less time in REM sleep. The iPad readers had reduced secretion of melatonin, a hormone which normally rises in the evening and plays a role in inducing sleepiness. Additionally, iPad readers had a delayed circadian rhythm, indicated by melatonin levels, of more than an hour. Participants who read from the iPad were less sleepy before bedtime, but sleepier and less alert the following morning after eight hours of sleep. Although iPads were used in this study, BWH researchers also measured other eReaders, laptops, cell phones, LED monitors, and other electronic devices, all emitting blue light.
"In the past 50 years, there has been a decline in average sleep duration and quality," stated Charles Czeisler, PhD, MD, FRCP, chief, BWH Division of Sleep and Circadian Disorders. "Since more people are choosing electronic devices for reading, communication and entertainment, particularly children and adolescents who already experience significant sleep loss, epidemiological research evaluating the long-term consequences of these devices on health and safety is urgently needed."
Researchers emphasize the importance of these findings, given recent evidence linking chronic suppression of melatonin secretion by nocturnal light exposure with the increased risk of breast cancer, colorectal cancer and prostate cancer.

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Story Source:
The above story is based on materials provided by Brigham and Women's Hospital. Note: Materials may be edited for content and length.

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Journal Reference:

1. Anne-Marie Chang, Daniel Aeschbach, Jeanne F. Duffy, and Charles A. Czeisler. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. PNAS, December 22, 2014 DOI: 10.1073/pnas.1418490112

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