Abstract 15044: Oxygen Uptake at Aerobic Thresholds During Exercise Testing, Cardiovascular and All-Cause Mortality Outcomes
Introduction: Cardiorespiratory fitness (CRF) is independently and inversely associated with cardiovascular outcomes. Oxygen uptake (VO2) at aerobic thresholds, which can be defined at submaximal exercise levels, is a proxy for CRF. However, the association of VO2 at aerobic thresholds, with fatal cardiovascular events and all-cause mortality has not been previously investigated.
Hypothesis: Oxygen uptake at aerobic thresholds may be associated with risk of sudden cardiac death (SCD), fatal coronary heart disease (CHD), fatal cardiovascular disease (CVD), and all-cause mortality.
Methods: Oxygen uptake at aerobic thresholds was assessed during a maximal, symptom-limited exercise test using respiratory gas analyzers in 1,674 middle-aged men (mean age 52 years) in the KIHD population-based cohort study. Hazard ratios (95% confidence intervals [CI]) were calculated for SCD, fatal CHD and CVD events, and all-cause mortality.
Results: During a median follow-up of 25.6 years, 138 SCDs, 210 fatal CHDs, 336 fatal CVDs, and 723 all-cause mortality events were recorded. Oxygen uptake at aerobic thresholds was linearly associated with each of these outcomes. Comparing the top versus bottom quartile of VO2 at aerobic thresholds, the age-adjusted hazard ratios (95% CIs) for SCD, fatal CHD, fatal CVD, and all-cause mortality were 0.24 (0.14-0.41), 0.24 (0.15-0.37), 0.36 (0.26-0.50), and 0.51 (0.41-0.63) respectively. After adjustment for measures of adiposity, socio-economic status, medical history, smoking status, systolic blood pressure, alcohol consumption, physical activity, heart rate and lipids, the corresponding hazard ratios were 0.40 (0.22-0.71), 0.37 (0.23-0.59), 0.55 (0.39-0.78), and 0.64 (0.51-0.81).
Conclusions: Oxygen uptake at aerobic thresholds, is an independent predictor of cardiovascular and all-cause mortality outcomes. Further research is warranted to assess the potential additional value of this sub-maximal level exercise testing method in predicting these major outcomes.
Figure Hazard ratios for sudden cardiac death, fatal coronary heart disease, fatal cardiovascular disease, and all-cause mortality by quartiles of oxygen uptake at aerobic threshold during exercise testing
Author Disclosures: S.K. Kunutsor: None. H. Khan: None. F. Zaccardi: None. R. Rauramaa: None. J.A. Laukkanen: None.
- © 2016 by American Heart Association, Inc.