80/20 polarized model · 4.25hrs Zone 2 · Norwegian 4×4 · 3× resistance · 4× sauna · Evidence-based longevity
3× less time · 92% vs 78% compliance · 96% satisfaction · Beyer 2015 RCT n=58
No turnover after ~age 17 · Heinemeier ¹⁴C bomb-pulse 2013 · periphery still adapts
Lifelong exercisers: -21% AGE cross-links · no mechanical decline vs young · Couppé 2014
+65% stiffness at 80% 5RM · zero adaptation at 40% 1RM · threshold is binary not gradient