Katherine Dudley, MD, MPH

Many people now wear smartwatches and other wrist-based devices, and use them to collect and track information about their sleep. But the algorithms that govern how the devices work are opaque, and there is no data comparing them to devices that sleep researchers use.

Trying to make up for not getting enough sleep during the week by sleeping longer on weekends has been found to have negative effects such as weight gain, expending less energy, and increased calorie intake during evenings.