Why Deep Sleep Declines Differently by Sex

Why do men and women age so differently when it comes to sleep? It turns out that

one of the most famous markers of aging—the decline of deep, slow-wave sleep—might

actually only apply to half the population. Large-scale data shows that men experience a dramatic,

cross-sectional drop in deep sleep as they get older. But for women? That deep sleep

stage, known as N3, stays remarkably stable, showing almost no

appreciable decline across the lifespan. This means a woman in her 70s might have the deep sleep

profile of someone much younger, while her male peers are seeing a significant biological shift.

We’re digging into the gendered science of sleep and the "biomarkers" of aging in our latest