Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
Center for Active and Healthy Ageing (CAHA), Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
J Gerontol A Biol Sci Med Sci. 2024 Jul 1;79(7). doi: 10.1093/gerona/glae120.
Multiples of resting metabolic rate (RMR) are often used to classify physical activity intensity, a concept known as the metabolic equivalent of task (MET). However, the METs metrics may misclassify physical activity intensity in older adults because of age-related changes in RMR and maximal aerobic capacity (V˙O2max). This study aimed to (i) compare classifications of activity intensity by estimated (METsestimated) and measured (METsmeasured) METs and (ii) compare physical activity classified by absolute (METsmeasured) versus relative intensity (%V˙O2Reserve) in older adults.
Ninety-eight adults aged 75-90 years participated in the study. RMR and V˙O2 during sitting, standing, daily activities, and 6-minute walking test were measured. V˙O2Reserve was defined as the difference between V˙O2max and RMR. Moderate and vigorous intensity was classified as 3 and 6 METs and 40% and 60% of V˙O2Reserve, respectively. Paired t tests and a confusion matrix were used to investigate aims 1 and 2, respectively.
METsmeasured was 24% lower than the standard 1 MET of 3.5 mL O2·min-1·kg-1. METsestimated underestimated the intensity during daily and walking activities when compared to METsmeasured. Nevertheless, when comparing METsmeasured to percentages of V˙O2Reserve, a mismatch was shown for moderate intensity in 47%-67% of the participants during daily activities and 21% of the participants during self-selected gait speed.
Applying METsestimated for older adults leads to potential underestimation of physical activity intensity, suggesting that current classification metrics should be revised for older adults. V˙O2Reserve is a candidate metric for establishing precise physical activity intensity cut points for older adults. Clinical Trials Registration Number: NCT04821713.
静息代谢率（RMR）的倍数常用于对身体活动强度进行分类，这一概念被称为代谢当量任务（MET）。然而，由于老年人 RMR 和最大有氧能力（V˙O2max）的年龄相关变化，METs 指标可能会错误分类身体活动强度。本研究旨在：（i）比较通过估计（METsestimated）和测量（METsmeasured）MET 估计的活动强度分类；（ii）比较通过绝对（METsmeasured）和相对强度（%V˙O2Reserve）分类的老年人身体活动。
98 名年龄在 75-90 岁的成年人参加了这项研究。测量了坐姿、站立、日常活动和 6 分钟步行测试时的 RMR 和 V˙O2。V˙O2Reserve 定义为 V˙O2max 和 RMR 之间的差异。中等强度和高强度分别被定义为 3 和 6 METs，40%和 60%的 V˙O2Reserve。采用配对 t 检验和混淆矩阵分别对目标 1 和 2 进行研究。
METsmeasured 比标准的 3.5 ml O2·min-1·kg-1 的 1 MET 低 24%。与 METsmeasured 相比，METsestimated 低估了日常活动和步行活动期间的强度。然而，当将 METsmeasured 与 V˙O2Reserve 的百分比进行比较时，在日常活动中，47%-67%的参与者和 21%的参与者在自我选择的步行速度下，中等强度的匹配存在差异。
对于老年人应用 METsestimated 可能会导致身体活动强度的潜在低估，这表明当前的分类指标应该针对老年人进行修订。V˙O2Reserve 是为老年人建立精确身体活动强度切点的候选指标。临床试验注册号：NCT04821713。
