Study Explains Why Sleep Loss is Tied to Diabetes Risk
While numerous studies have identified links between insufficient sleep, weight gain, and type 2 diabetes, a new study in the journal Diabetologia may be one of the first to identify a potential mechanism explaining the connection.
“We found that sleep restriction resulted in an increase in late-night and early-morning fatty acid levels,” says lead study author Josiane Broussard, PhD, a research scientist at Cedars-Sinai Medical Center’s Diabetes and Obesity Research Institute in Los Angeles. “The nocturnal elevation of fatty acids from about 4 a.m. to 6 a.m. correlated with an increase in insulin resistance—a hallmark of pre-diabetes.”
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Broussard and her colleagues recruited 19 healthy men, ages 18 to 30. They monitored each subject in two different sleep scenarios, which were conducted in randomized order and spaced at least 1 month apart:
• In one, they got a full night’s rest—8.5 hours in bed (averaging 7.8 hours asleep) during 4 consecutive nights.
• In the other, they spent just 4.5 hours in bed (averaging 4.3 hours asleep) for 4 consecutive nights.
The researchers found that sleep restriction resulted in a 15% to 30% increase in late-night and early-morning fatty acid levels. While these levels usually peak and then decline overnight, after 3 nights of getting just 4 hours of sleep, they remained elevated in the subjects from about 4 a.m. to 9 a.m.
There was a correlation between fatty acid and insulin resistance. As long as the fatty acid levels remained high, the ability of insulin to regulate blood sugars was reduced.
Glucose levels were unchanged, but the ability of available insulin to regulate blood glucose levels decreased by about 23% after the shorter sleep interval—a sign the authors believe may suggest an insulin-resistant state.
“These findings suggest that sleep plays a role in regulating lipid metabolism, which is altered/impaired in obesity, diabetes, and cardiovascular disease,” Broussard says.
The findings also suggest that simply getting some more shut eye could help counteract diabetes and obesity.
Broussard and her colleagues plan to continue investigating this mechanism.
“We are interested in many different ways to improve metabolism—either with sleep extension or when that is not possible, diet and exercise interventions,” she says.
—Colleen Mullarkey
Reference
Broussard JL, Chapotot F, Abraham V, Day A, Delebecque F, Whitmore HR, Tasali E. Sleep restriction increases free fatty acids in healthy men. Diabetologia. 19 February 2015. doi: 10.1007/s00125-015-3500-4.