Even one week of not getting eight hours of sleep can alter a person’s capacity to metabolize carbohydrates.
Researchers at the University of Chicago investigated the consequences of sleep deprivation on blood sugar and hormone levels. They conclude that type 2 diabetes, as well as high blood pressure, obesity and memory loss, are all risk factors for people who have chronic sleep loss.
Dr. Eve Van Cauter, lead investigator on the sleep study, which was published in the October 23 issue of The Lancet, says that people who trade sleep for work or play may get used to it and feel less fatigue, but their bodies will pay a physical price.
“…An adequate amount of sleep is as important as an adequate amount of exercise,” says Van Cauter. “Sleeping is not a sin.”
Eleven healthy men, ages 18 to 27, were observed for 16 consecutive nights. On the first three nights the men slept for eight hours. For the next six nights the men slept for only four hours, and for the last seven nights they slept for 12 hours. All men followed the same diet and had their blood sugar levels monitored, as well as several other hormones involved in metabolism.
During sleep depravation, the subjects’ blood sugar levels took 40 percent longer to drop following a diet high in carbohydrates, compared with the sleep recovery period. Their ability to secrete and respond to insulin also dropped by 30 percent when deprived of sleep.
In addition, the researchers say that the sleep-deprived men had higher nighttime concentrations of the hormone cortisol, which also helps regulate blood sugar. Raised cortisol levels are often seen in older people, and may be involved in age-related insulin resistance and memory loss.
Previous research has shown that in developed countries, the average night’s sleep has decreased from nine hours to seven and a half hours since the beginning of the century.