Cardiorespiratory fitness, muscle strength and risk of cardiovascular outcomes
Physical fitness is associated with lower cardiovascular disease (CVD) mortality, with multiple studies demonstrating a consistent, inverse association between cardiorespiratory fitness (CRF) and mortality even after adjustment for the traditional risk factor burden (1,2). This association has persisted across the lifespan, as a single measurement of CRF in midlife is strongly associated with the lifetime risk for cardiovascular mortality decades later. Cardiorespiratory fitness is associated with a reduced risk of several adverse health outcomes (3-9). Although CRF is recognized as an important marker of both functional ability and cardiovascular health, it is currently one of the most important risk factors that is not routinely and regularly assessed in either the general or specialized clinical setting. The relationship between CRF and other nonfatal cardiovascular outcomes is not well understood, which reflects the limited data on nonfatal cardiovascular events including atrial fibrillation, heart failure (HF) and stroke with objectively measured physical fitness and muscle strength. Much of the focus on the mechanisms of benefit of physical exercise and CRF have focused on prevention of atherosclerosis and its complications, although the specific effects of physical exercise on cardiac and vascular function suggest that low CRF might be an important risk factor for HF and other nonfatal cardiovascular events (10).