RUN LONG, RUN HEALTHY — OCTOBER 2, 2025

Could Hard Evening Runs Sabotage Your Sleep?

A new study of more than 14,000 WHOOP users finds that exercising too hard too close to bedtime might spell trouble.

Over the past several years, a growing body of evidence has solidified what many of us already suspected (or have personally experienced): regular physical activity can significantly improve sleep.

Exercise enhances both how much we sleep (the quantity) and how well we sleep (the quality). It helps people fall asleep faster, sleep longer, and spend more time in deep, restorative stages of sleep. These benefits are observed across a wide range of exercise types, including aerobic, resistance, and mind-body modalities, and hold for people with sleep difficulties like insomnia. While the improvements are not usually dramatic (we’re talking on the order of minutes or small percentage points), they are meaningful, especially for anyone struggling with sleep or feeling unrested.

Importantly, these improvements aren’t just subjective. Objective sleep metrics like sleep efficiency and slow-wave sleep duration also trend upward with regular training. While a single workout can lead to modest gains in sleep on the same night, the biggest benefits…