Kominami Kazuyuki, Imahashi Keiko, Katsuragawa Toko, Murakami Mitsuyo, Akino Masatoshi
Cardiac Rehabilitation Center, Sapporo Ryokuai Hospital, Sapporo, Japan.
Department of Cardiovascular Medicine, Sapporo Ryokuai Hospital, Sapporo, Japan.
Front Physiol. 2022 Mar 3;13:769387. doi: 10.3389/fphys.2022.769387. eCollection 2022.
The period from ventilatory anaerobic threshold (VAT) to respiratory compensation point (RCP) during incremental exercise (isocapnic buffering phase) has been associated with exercise tolerance and skeletal muscle composition. However, several reports compare younger and older healthy adults, and specific age-related changes are unclear. This study aimed to examine the oxygen uptake (VO) from VAT to RCP and its change over time in younger and older healthy adults.
A total of 126 consecutive participants were divided into two groups (95 younger and 31 older than 50 years of age) who underwent cardiopulmonary exercise testing, and VAT and RCP were determined. The ratio (RCP/VAT) and difference (ΔVO RCP-VAT) were calculated from the VO of VAT and RCP and compared between groups and ages. Statistical analyses included -tests and Spearman's correlation tests, and the significance level was set at <5%.
RCP/VAT was not significantly different (1.40 ± 0.19 vs. 1.59 ± 0.24, = 0.057) but weakly correlated with age ( = -0.229, = 0.013, = -0.0031x + 1.7588, lowering rate: 0.185%/year). Conversely, ΔVO RCP-VAT was significantly lower in the older group (7.7 ± 3.1 vs. 13.8 ± 4.9 ml/kg/min, < 0.001) and correlated significantly with age ( = -0.499; < 0.001; = -0.1303x + 16.855; lowering rate, 0.914%/year).
ΔVO RCP-VAT was considered to be a poor indicator of lactate buffering capacity in the IB phase because both VAT and RCP were greatly affected by age-related decline. Conversely, RCP/VAT was suggested to be an index not easily affected by aging.
在递增运动（等碳酸缓冲阶段）过程中，从通气无氧阈（VAT）到呼吸补偿点（RCP）的阶段与运动耐力和骨骼肌组成有关。然而，一些报告比较了年轻和年长的健康成年人，但具体的年龄相关变化尚不清楚。本研究旨在检查年轻和年长健康成年人从VAT到RCP的摄氧量（VO）及其随时间的变化。
共有126名连续参与者被分为两组（95名年轻人和31名50岁以上的老年人），他们接受了心肺运动测试，并确定了VAT和RCP。根据VAT和RCP的VO计算比率（RCP/VAT）和差值（ΔVO RCP-VAT），并在组间和年龄间进行比较。统计分析包括t检验和Spearman相关性检验，显著性水平设定为<5%。
RCP/VAT无显著差异（1.40±0.19对1.59±0.24，P = 0.057），但与年龄呈弱相关（r = -0.229，P = 0.013，y = -0.0031x + 1.7588，下降率：0.185%/年）。相反，老年组的ΔVO RCP-VAT显著较低（7.7±3.1对13.8±4.9 ml/kg/min，P < 0.001），且与年龄显著相关（r = -0.499；P < 0.001；y = -0.1303x + 16.855；下降率，0.914%/年）。
ΔVO RCP-VAT被认为是等碳酸缓冲阶段乳酸缓冲能力的一个较差指标，因为VAT和RCP都受到年龄相关下降的极大影响。相反，RCP/VAT被认为是一个不易受衰老影响的指标。
