For how we live.
In 425 US adolescents followed with phone sensors and Fitbits across 7,591 nights, heavier-than-usual late-evening phone use tracked with later, shorter sleep — the association growing hour by hour toward midnight.
Two NCAA surveys nine weeks apart put the share of Division I men's basketball players receiving abuse tied to betting at 36% and 46%. The gap between them is the most informative part.
A meta-analysis of six studies found a moderate effect on sleep duration and a small one on depressive symptoms — with high heterogeneity on both.
The clearance story about sleep has been brain-centric. A Nature paper reports that in Drosophila, immune cells from the circulation do part of the job — and that blocking them shortens sleep.
Among 16-to-24-year-olds in NHANES, those who slept longer on weekends had 41% lower odds of daily depressive symptoms. The survey measured both at the same moment, which limits what can be concluded.