What does VO2max have to do with sexual stamina?

Sexual activity in men requires an energy expenditure of approximately 3–5 METs (metabolic equivalents), equivalent to a moderate walk or low-intensity cycling, meaning a man with a VO2max below 8 METs is operating at 50–60% of his cardiovascular ceiling during sex, likely experiencing exertional discomfort, whereas a man with VO2max above 12 METs is operating at 25–40% of capacity, experiencing sex as physiologically comfortable and unremarkable (DeBusk et al., Am J Cardiol, 200001118-1)).

The cardiac rehabilitation literature first quantified the metabolic cost of sexual activity because cardiologists needed to counsel post-cardiac event patients about when it was safe to resume sex. The energy demand of sex is not dramatically different from climbing two flights of stairs. A man who cannot climb two flights of stairs without chest tightness or significant breathlessness should discuss cardiovascular evaluation before resuming sexual activity after a cardiac event. For healthy men, the practical implication is that maintaining VO2max above 10–12 METs is the fitness threshold below which sexual stamina is typically preserved.

Honesty Scale: Solid (1) for the MET-based quantification of sexual activity energy demand and its relationship to VO2max.

What to do: If you want a concrete VO2max estimate, use the Rockport 1-mile walk test (walk 1 mile as fast as possible and measure time and heart rate at completion, plug into the formula or use an online calculator). If your estimated VO2max is below 8 METs, prioritize aerobic base building before any other health optimization work.

For the full picture, read The Stamina Deep Dive