People with diabetes or those who need to manage their blood sugar should secure enough sleep before worrying about their diet, according to an expert. Too little sleep weakens the body's insulin response and increases cravings for high-calorie foods, making blood sugar harder to control.
Aditya Phadte, an endocrinologist in India, said in an interview with the local outlet NDTV on the 2nd that while sweet desserts raise blood sugar temporarily, the effects of falling short on sleep every night last far longer. If the pattern continues, he said, it can progress through insulin resistance and impaired glucose tolerance to type 2 diabetes.
A lack of sleep activates the sympathetic nervous system and increases secretion of cortisol, a stress hormone. Cortisol prompts the liver to release glucose into the bloodstream, pushing blood sugar higher. Over time, cells become less sensitive to insulin, making blood sugar harder to regulate.
Research has put numbers to the effect. In a study of 36 people published in the journal Current Biology in 2019, a group that slept five hours a night for nine days saw whole-body insulin sensitivity fall 13%. A 2015 paper in the same journal found that insulin sensitivity dropped 20% in 16 healthy young adults who slept five hours a night for five days.
Dutch researchers reported that insulin action weakened in nine healthy adults after a single night of four hours' sleep, compared with after eight hours. All three studies used healthy young adults as participants, so the findings cannot be applied directly to people with diabetes.
Appetite is also affected. Insufficient sleep raises levels of ghrelin, which stimulates appetite, and lowers leptin, which signals fullness. A 2013 paper in Nature Communications used functional magnetic resonance imaging (fMRI) to scan the brains of 23 healthy young adults, comparing results after adequate sleep and after a night without sleep.
After the sleepless night, desire for high-calorie foods and activity in the amygdala both increased. Participants reported no difference in how hungry they felt under the two conditions. The researchers concluded that the sleep deprivation itself, rather than hunger, was the cause. Excessive intake of high-calorie foods leads to obesity, which makes blood sugar control still more difficult.
Diabetes UK recommends seven to nine hours of sleep a night. Counting back from the time one needs to wake up, going to bed at a similar hour each day helps, and drinking alcohol or using a smartphone before bed should be avoided. Still, some research links more than nine hours of sleep to a higher risk of diabetes, so staying within the recommended range is advisable.
Snoring, pauses in breathing during sleep and severe morning headaches can be signs of sleep apnea. Treating a sleep disorder can improve insulin sensitivity.
