When the effort stops, pulse and breathing do not: they fall back only gradually — the recovery phase. The body is settling debts: reloading its oxygen stores, clearing the effort’s wastes, shedding the accumulated heat. The fitter the body, the faster its recovery — which is why recovery time is itself a fitness measurement.
Examples
Example 49.8 (Two runners, one hill)
Untrained and trained run the same hill. Untrained: pulse at halfway, gasping, forced to walk — the supply lines cannot pay the bill, and the debt calls a halt. Trained: pulse at the top, speech possible, recovery in three minutes. Same hill, same bill — different ceilings, built by months of exactly such hills taken gently.