What lifestyle changes have the best evidence for improving stamina in men 40–55?

The five lifestyle interventions with the most consistent evidence for improving both cardiovascular and sexual stamina in men 40–55, ranked by effect size: (1) aerobic exercise (150+ min/week zone 2), the single most powerful intervention; (2) visceral fat reduction through diet and exercise, measurably improves testosterone and endothelial function; (3) alcohol reduction or elimination, removes a direct NO-pathway suppressant; (4) sleep restoration (7–8 hours with treated sleep apnea), recovers overnight testosterone synthesis and parasympathetic recovery; (5) smoking cessation if applicable, one of the most aggressive endothelial damage drivers (Derby et al., J Urol, 200067651-7)).

None of these require a prescription. All of them are within a man's control. The reason this list is presented in this order is that men often pursue the least evidence-supported interventions first (supplements, devices, hormone therapy) while postponing the most evidence-supported ones (exercise, sleep, alcohol reduction) because the latter require sustained behavioral change. The cardiologist's direct statement: if you have not yet built consistent aerobic training into your week, no other intervention for stamina will come close to its effect.

Honesty Scale: Solid (1) for all five interventions based on their respective evidence bases.

What to do: Build 150 minutes of zone 2 training into this week before purchasing a supplement or device for stamina. Track your resting heart rate over 90 days of consistent zone 2 training, a drop of 5–10 bpm is the objective evidence that cardiovascular adaptation is occurring.

For the full picture, read The Stamina Deep Dive