How many rest days should runners take?

Rest days are when adaptation actually happens — the hard sessions are the stimulus, recovery is the response. Skipping rest days means you're never capitalizing on the training you did. For beginners running 3 times per week, the non-run days should all be rest or active recovery (walking, yoga, easy cycling). For intermediate runners doing 4-5 runs per week, one full rest day is the minimum. For experienced runners doing 5-6 runs per week, you still need at least one no-running day, typically the day after the long run or a quality session. Elite runners who run 6-7 days per week usually include one 'double easy' day that functions as near-rest. Full rest means no structured exercise — you can walk, stretch, or foam roll, but nothing that generates fatigue. Active recovery is different: 20-30 minutes of very easy movement (cycling, swimming, walking) that promotes blood flow without adding stress. The signs you need more rest: resting heart rate elevated 5+ bpm, sleep disturbed, legs feel heavy 48 hours after hard sessions, motivation dropping, or minor aches becoming persistent. Take the rest before the injury forces you to.