Schedule recovery days in training.
Scheduling recovery works from load rather than from how you feel, because feel lags. Sport science quantifies a session as perceived exertion multiplied by duration — the session-RPE method — which gives a single number in arbitrary units that combines how hard and how long. Summed across the week it becomes weekly load, and comparing that against what a given profile tolerates is what determines how many recovery days the week needs. Tolerance is not fixed: it falls by roughly one percent a year past thirty as tissue turnover and hormonal recovery slow, and it rises with training history, so an advanced lifter handles perhaps a quarter more load than a beginner attempting the same programme. The spacing figure matters as much as the count — a session at RPE 9 needs the better part of two days before the same tissue is loaded hard again.
Session-RPE load and recovery day requirement
Session load = RPE x minutes; weekly load = session load x sessions; tolerable load = 2800 / (age factor x experience factor); recovery days = round(weekly load / tolerable load x 2.4), bounded 1-5; hours between hard sessions = 24 + 9 x (RPE - 5) x age factor
General training-load guidance, not medical advice or individualised coaching. Persistent fatigue, declining performance, elevated resting heart rate or disturbed sleep can indicate overtraining or an underlying condition — consult a qualified coach or health professional rather than pushing through.
Because what changes with age is recovery speed, not trainability. Older athletes adapt well to the same stimulus but need more time between hard sessions, so the same weekly programme spread over more days works better than reducing intensity.
For different tissue, yes — a hard lower body session and a hard upper body session can sit back to back. For the same movement pattern at RPE 8 or above, the spacing figure here is a better guide.
A relative scale, not a physical quantity. Sixty minutes at RPE 7 is 420 AU. The number is only meaningful compared with your own previous weeks, which is exactly how coaches use it to spot spikes that precede injury.