Oxygen uptake efficiency slope (oues) calculated at submaximal intensities is related to mortality in apparently healthy adults from the Ball St cohort

Abstract

The purpose of this study was to determine the relationship between submaximal oxygen uptake efficiency slope derived from a maximal test and all-cause mortality in apparently healthy adults from the Ball State Adult Fitness Longitudinal Lifestyle Study (BALL ST) cohort. Of the 2,220 participants who completed a treadmill protocol cardiopulmonary exercise test (CPET) from 1971 to 2018, there were 310 all-cause mortalities. During this time, the average follow-up was 20.2 ± 11.1 years. OUES was calculated using 50% and 75% of the baseline CPET time. To determine the relationship between OUES from 50% (OUES50) and OUES from 75% (OUES75) of the CPET with allcause mortality, Cox-proportional hazard models were utilized. OUES50 was inversely related to all-cause mortality when adjusted for age, sex, and test year (hazard ratio [HR]: 0.903; 95% confidence interval [CI]: 0.821-0.994). OUES75 was inversely related to allcause mortality after adjustment for age, sex, and test year (HR: 0.837; CI: 0.730-0.959), and after further adjustment for obesity, hypertension, dyslipidemia, diabetes, physical activity, and smoking. (HR: 0.862; CI: 0.750-0.992). Neither OUES50 nor OUES75 had a significant relationship with all-cause mortality in an unadjusted model or adjusting for the traditional cardiovascular risk factors when maximal oxygen uptake (VO2max) was included. The current study is novel because it is the first of its kind to assess the relationship between OUES calculated at a submaximal intensity and all-cause mortality in apparently healthy adults. OUES may be clinically useful when it is not appropriate for maximal exercise, or when previous submaximal exercise had been performed.