Geriatric Research, Education, and Clinical Center, Durham VA Medical Center, Durham, NC, USA.
Med Sci Sports Exerc. 2013 Mar;45(3):574-82. doi: 10.1249/MSS.0b013e318276c73c.
This study aimed to measure the metabolic cost (METs) of walking activities in older adults, to examine the relationship between accelerometer output and METs across walking activities, and to compare measured MET values in older adults with the MET values in the compendium.
Twenty older adults (mean age = 75, range = 60-90 yr) completed eight walking activities (five treadmill based, three free living) for 6 min each. Oxygen consumption (V˙O2) and resting metabolic rate (RMR) were measured using a portable metabolic system, and motion was recorded using a waist-mounted ActiGraph accelerometer (GT3X; ActiGraph, Pensicola, FL). Energy expenditure across activities was defined as kilocalories per minute and measured as METs (V˙O2 / RMR) and standard METs (V˙O2 / 3.5 mL·kg-1·min-1). Mixed modeling was used to assess differences in counts per minute and kilocalories per minute by weight status, sex, comorbidity status, and functional status. Linear regression analysis was applied to develop a prediction equation for kilocalories per minute. Energy costs of walking were subsequently compared with METs in the compendium of physical activities.
Average measured RMR was 2.6 mL·kg-1·min-1, 31.6% less than the standard RMR of 3.5 mL·kg-1·min-1. On average, standard METs were 71% lower than the measured METs across all walking activities. Measured MET levels differed from previously reported values in the literature and values listed in the compendium, resulting in misclassification of activity intensities for 60% of the walking conditions. Average counts for the walking activities ranged from 809 (treadmill = 1.5 mph) to 4593 counts per minute (treadmill = 3.5 mph). Previous regression equations consistently overestimate all activities compared with the measured energy cost in this sample of older adults.
This study identifies the need for equations and cut points specific to older adults.
本研究旨在测量老年人行走活动的代谢成本（METs），检验计步器输出与行走活动 METs 之间的关系，并比较老年人的实测 MET 值与纲要中的 MET 值。
20 名老年人（平均年龄=75 岁，范围 60-90 岁）完成 8 种行走活动（5 种跑步机，3 种自由生活），每种活动持续 6 分钟。使用便携式代谢系统测量耗氧量（V˙O2）和静息代谢率（RMR），使用腰部佩戴的 ActiGraph 加速度计（GT3X；ActiGraph，彭萨科拉，FL）记录运动。活动过程中的能量消耗定义为每分钟千卡数，并用代谢当量（V˙O2 / RMR）和标准代谢当量（V˙O2 / 3.5mL·kg-1·min-1）表示。混合模型用于评估体重状况、性别、合并症状况和功能状态对每分钟计数和千卡数的差异。线性回归分析用于建立每分钟千卡数的预测方程。随后将行走的能量消耗与活动纲要中的代谢当量进行比较。
平均实测 RMR 为 2.6mL·kg-1·min-1，比标准 RMR（3.5mL·kg-1·min-1）低 31.6%。平均而言，标准 METs 比所有行走活动的实测 METs 低 71%。实测 MET 水平与文献中的先前报道值和活动纲要中的列出值不同，导致 60%的行走条件活动强度分类错误。行走活动的平均计数范围为 809（跑步机=1.5mph）至 4593 计数/分钟（跑步机=3.5mph）。以前的回归方程始终高估了与本老年人样本实测能量消耗相比的所有活动。
本研究确定了需要针对老年人制定特定的方程和切点。
