Background 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 (V̇O2max). This study aimed to 1) compare classifications of activity intensity by estimated (METsestimated) and measured (METsmeasured) METs and 2) compare physical activity classified by absolute (METsmeasured) versus relative intensity (%V̇O2Reserve) in older adults. Methods Ninety-eight adults aged 75-90 years participated in the study. RMR and V̇O2 during sitting, standing, daily activities and 6-minute-walking-test were measured. V̇O2Reserve was defined as the difference between V̇O2max and RMR. Moderate and vigorous intensity was classified as 3 and 6 METs and 40% and 60% of V̇O2Reserve, respectively. Paired t-tests and a confusion matrix were used to investigate aim 1 and 2, respectively. Results 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 V̇O2Reserve, 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. Conclusion Applying METsestimated for older adults leads to potential underestimation of physical activity intensity, suggesting that current classification metrics should be revised for older adults. V̇O2Reserve is a candidate metric for establishing precise physical activity intensity cut-points for older adults.

中文翻译：

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需要修改老年人体力活动强度的分类吗？使用估计的 MET、测量的 MET 和 V̇O2 储备

背景 静息代谢率 (RMR) 的倍数通常用于对体力活动强度进行分类，这一概念称为任务代谢当量 (MET)。然而，由于 RMR 和最大有氧能力 (V̇O2max) 与年龄相关的变化，MET 指标可能会对老年人的体力活动强度进行错误分类。本研究旨在 1) 比较按估计 (MET 估计) 和测量 (MET 测量) MET 进行的活动强度分类；2) 比较按老年人绝对强度 (MET 测量) 与相对强度 (%V̇O2Reserve) 分类的身体活动。方法 98 名 75-90 岁的成年人参与了这项研究。测量坐位、站立、日常活动和 6 分钟步行测试期间的 RMR 和 V̇O2。 V̇O2Reserve 定义为 V̇O2max 与 RMR 之间的差值。中等强度和剧烈强度分别分为 3 和 6 MET，以及 V̇O2 储备的 40% 和 60%。配对 t 检验和混淆矩阵分别用于研究目标 1 和 2。结果测得的MET比3.5 ml O2·min-1·kg-1的标准1 MET低24%。与测量的 MET 相比，MET 估计低估了日常活动和步行活动的强度。然而，当将测量的 MET 与 V̇O2 储备百分比进行比较时，47-67% 的参与者在日常活动中显示出中等强度的不匹配，21% 的参与者在自选步态速度中显示出不匹配。结论 对老年人应用 MET 估计可能会低估身体活动强度，这表明应针对老年人修改当前的分类指标。 V̇O2Reserve 是一个候选指标，用于为老年人建立精确的体力活动强度切点。