All-cause mortality and cardiorespiratory fitness (CRF) are negatively correlated. The relationship between CRF and mortality risk for various racial groups, women, and old people has not yet been thoroughly examined. For a study, researchers sought to analyze the relationship between CRF and mortality risk across the age, racial, and sex spectrums.

The participants included 750,302 U.S. veterans with ages ranging from 30 to 95 (mean age, 61.3±9.8 years), included septuagenarians (n = 110,637), octogenarians (n = 26,989), African Americans (n = 142,798), Hispanics (n = 35,197), Native Americans (n = 16,050), and women (n = 45,232). On the basis of the peak, METs attained during a standardized exercise treadmill test, age- and sex-specific CRF categories (quintiles and 98th percentile) were objectively created.

There were 174,807 subject deaths throughout follow-up (median 10.2 years; 7,803,861 person-years of observation), with an average of 22.4 occurrences per 1,000 person-years. With regard to age, sex, and race, the adjusted connection between CRF and mortality risk was graded in the opposite direction. For both men (HR: 0.24; 95% CI: 0.23-0.25) and women (HR: 0.23; 95% CI: 0.17-0.29), the lowest mortality risk was found at around 14.0 METs and there was no indication of an increase in risk with extremely high CRF. In comparison to people who are exceptionally fit, the risk for those who are in the 20th percentile of fitness was 4 times greater (HR: 4.09; 95% CI: 3.90-4.20).

The relationship between CRF and mortality risk was inverse, independent, and graded throughout the age range (including septuagenarians and octogenarians), males, women, and all races. Extreme fitness did not show to enhance the danger. No cardiac risk factor considered held a higher risk than being physically inactive.