Impact of Yo-Yo Sleep on Cardiometabolic Health

A large portion of the U.S. adult population reports insufficient sleep on a nightly basis. It has been shown that sustained insufficient sleep leads to adverse cardiometabolic risk profile and positive energy balance. However, sleep patterns in real life are not consistent over weeks. Individuals not obtaining sufficient sleep during the week may compensate by sleeping longer on weekends. The differences in sleep duration between week and weekend nights is approximately 1 hour, mostly due to delaying wake times rather than advancing bedtimes. A drawback of such behaviors is resultant change in sleep midpoint, which has been associated with adverse cardiometabolic health and obesity. However, very few studies have attempted to determine whether recovery sleep on weekends results in reversal of adverse health effects of insufficient sleep during the week. Available studies suggest that recovery sleep does not revert health markers to pre-sleep restriction (SR) levels. But these studies are short, usually involving only one cycle of SR followed by recovery sleep, and fail to use appropriate and robust statistical methods. Therefore, the goal of the current investigation is to evaluate the impact of repeated intermittent short sleep, with short sleep maintained 5 days/week followed by 2 days of recovery sleep, relative to daily adequate sleep, on energy balance and cardiometabolic risk markers. A secondary goal of this research is to determine if maintaining a constant sleep timing while undergoing intermittent short sleep, leads to better outcomes than intermittent short sleep in conjunction with shifts in sleep times.