Only catching up on sleep on the weekends, after losing sleep during the week, can lead to weight gain and a higher risk of diabetes, a new study suggests.
The researchers studied 36 healthy adults between the ages of 18 and 39 over ten days, according to NBC News. One group slept nine hours each night, and another group slept only five. A final group slept five hours a night for five days, slept for an unrestricted amount of time for two days, and were once again limited to five hours of sleep for another two nights.
This last group’s experience was intended to simulate the common practice of cutting down on sleep during the week before trying to catch up with extra sleep on the weekend.
Both of the sleep-deprived groups ate more snacks at night, and gained weight as a result. They also experienced a decline in their sensitivity to insulin, which is an early warning sign for diabetes. And while the “catch-up” group saw modest improvement during the days with more hours of sleep, they immediately returned to their bad habits when sleep-deprived once again.
“Our findings suggest that the common behavior of burning the candle during the week and trying to make up for it on the weekend is not an effective health strategy,” according to the study’s senior author, Kenneth Wright, director of the University of Colorado Boulder’s Sleep and Chronobiology Lab.
Uneven sleep schedules lead to a disruption of circadian rhythms – the internal patterns that affect the body’s processes through a 24-hour cycle. Irregular cycles can lead to lasting health effects such as obesity.
Sleep deprivation also interferes with the hormones that govern our appetite and ability to feel satisfied from food. Both become disrupted as a result of sleep loss, which also limits impulse control, leading people to consume more unhealthy food.
And while the sleep-deprived group saw a 13 percent decline in their insulin sensitivity, the “catch-up” group experienced more varied declines, from as low as 9 percent to as much as 27 percent.
For adults, the American Academy of Sleep Medicine recommends at least seven hours of sleep nightly for adults.
In 2013, the last year measured by Gallup polling, Americans were getting 6.8 hours of sleep each night, down an hour from 1942. In 1910, Americans slept an average nine hours every night. In the 2013 poll, 40 percent of Americans reported getting less than six hours each night.
The new study was published Thursday in the journal Current Biology.