Training heart-rate zones, VO₂ estimates and one-rep-max references — with the practical limits of each estimate.
Karvonen-based 5-zone training ranges from age and resting HR (Tanaka + ACSM 2022).
Estimate cardiorespiratory fitness non-invasively (Uth 2004) with ACSM percentile norms.
Epley + Brzycki 1RM prediction with NSCA %1RM training-zone loads.