For how we live.
Every article we have published on Cardiorespiratory Fitness, newest first.
A large treadmill cohort found the least-fit adults had about five times the death rate of the fittest — a bigger risk than coronary disease, smoking or diabetes. But it measures a state, not a lever.
In a 64-patient randomised trial, home cardiac rehab monitored by a smart ring improved fitness. But both arms wore the ring; what separated them was a weekly call from a clinician.
In 25,241 non-exercisers, three brief daily bursts of vigorous activity tracked with markedly lower mortality. A small trial found stair-climbing 'snacks' raised fitness. The catch: they must be genuinely vigorous.
Meta-analyses put high-intensity intervals roughly 1.2 mL/kg/min ahead of continuous training for peak oxygen uptake. Both produce large gains; the format you will keep doing wins.
A sibling-controlled cohort of 1.1 million men, a genetic analysis of 712 traits and a UK Biobank study of fitness change converge — and they agree on where the exception is.
Against a laboratory gas-exchange test, the Series 10 underestimated VO2 max by about 6 mL/kg/min on average, with wide limits of agreement. It reads trends better than absolute numbers.
A review found wearables gave valid maximal-oxygen-uptake estimates in most studies of untrained and recreational exercisers. A separate meta-analysis pooled a 0.83 correlation, with high variability.
Nearly a million conscripts followed for three decades: obesity carried a 3.1-fold hazard for sepsis, and high cardiorespiratory fitness was associated with a 42% lower risk of dying from bacterial infection.