Sleep loss can elevate levels of free fatty acids in the blood among those with pre-diabetic conditions, says new study, confirming a 15-year-old study on the same lines.
The study, however, could link for the first time sleep loss to diabetes with more evidence collected for 24 hours about the fatty acid levels in the blood due to insufficient sleep that afflicts the modern youth mostly.
“At the population level, multiple studies have reported connections between restricted sleep, weight gain, and type 2 diabetes,” said Esra Tasali, assistant professor of medicine at the University of Chicago. “Experimental laboratory studies, like ours, help us unravel the mechanisms that may be responsible.”
The researchers found that after three nights of getting only four hours of sleep, blood levels of fatty acids, which usually peak during the day and recede overnight, remained elevated from about 4 a.m. to 9 a.m. When fatty acid levels are high, the ability of insulin to regulate blood sugars is reduced.
In fact, 15 years ago Chicgo researchers warned about the link between sleep loss, insulin resistance and heightened risk of type 2 diabetes.
The researchers studied 19 healthy male subjects aged between 18 and 30 in two two scenarios — one, they got a full night’s rest–8.5 hours in bed for four nights and the other spent just 4.5 hours in bed for four consecutive nights. Both the studies were held a month apart.
Constant monitoring and collection of samples helped researchers measure blood levels of free fatty acids and growth hormone, glucose and insulin, and the stress hormones noradrenaline and cortisol. After 4 nights, an intravenous glucose-tolerance test was also performed.
They found that sleep restriction resulted in a 15% to 30% increase in late night and early morning fatty acid levels. The nocturnal elevation of fatty acids (from about 4 a.m. to 6 a.m.) correlated with an increase in insulin resistance, pointing at pre-diabetes that lasted for 5 hours.
Less sleep prolonged night-time growth hormone secretion that showed up in more noradrenaline in the blood, and both contribute to the increase in fatty acid levels.
Although glucose levels remained unchanged, the ability of available insulin to regulate blood glucose levels decreased by about 23% after a short sleep, suggesting, “an insulin-resistant state,” said the researchers.
Constantly elevated fatty-acid levels in the blood are usually seen in obese individuals as well as those with type 2 diabetes or cardiovascular disease. A previous study in 2012 by a related research team emphasized the connections between sleep loss and the disruption of human fat cell function in energy regulation.
The new findings have been published in Diabetologia, the journal of the European Association for the Study of Diabetes.