An Objective Method to Accurately Measure Cardiorespiratory Fitness in Older Adults Who Cannot Satisfy Widely Used Oxygen Consumption Criteria

摘要

Cardiorespiratory fitness (CRF) is routinely investigated in older adults; however, the most appropriate CRF measure to use for this population has received inadequate attention. This study aimed to 1) evaluate the reliability and validity of the oxygen uptake efficiency slope (OUES) as a sub-maximal measurement of CRF; 2) examine demographic, risk-factor, and exercise testing differences in older adults who satisfied standardized criteria for a peak oxygen consumption ((V)over dotO-2peak) test compared to those who did not; and 3) determine the difference between directly measured (V)over dotO-2peak values and OUES-predicted (V)over dotO-2peak values. One hundred ten enrollees from the Wisconsin Registry for Alzhei mer's Prevention participated in this study. Participants performed a graded maximal exercise test and wore an accelerometer for 7 days. For each participant, the OUES was calculated at 75%, 90%, and 100% of exercise duration. (V)over dotO-2peak was recorded at peak effort, and one week of physical activity behavior was measured. OUES values calculated at separate relative exercise durations displayed excellent reliability (ICC = 0.995; p 0.001), and were strongly correlated with (V)over dotO-2peak (r(range) = 0.801-0.909; p 0.001). As hypothesized, participants who did not satisfy (V)over dotO-2peak criteria were significantly older than those who satisfied criteria (p = 0.049) and attained a directly measured (V)over dotO-2peak that was 2.31 mL.kg.min(-1) less than the value that was predicted by OUES (V)over dotO-2peak (p = 0.003). Older adults are less likely to satisfy (V)over dotO-2peak criteria, which results in an underestimation of their CRF. Without adhering to standardized criteria, (V)over dotO-2peak measurement error may lead to misinterpretation of CRF and age-related associations. Here, we conclude that OUES is a reliable, valid measurement of CRF which does not require achievement of standardized criteria.