Department of Health and Human Performance, Marymount University, Arlington, United States.
Department of Exercise and Sport Science, University of Wisconsin-La Crosse, La Crosse, WI, United States.
Exp Gerontol. 2020 Sep;138:110984. doi: 10.1016/j.exger.2020.110984. Epub 2020 Jun 2.
Low muscle strength (dynapenia) is a primary characteristic of sarcopenia, the age-related loss of muscle mass and strength or low walking speed. New evidence suggests that muscle strength positively affects blood pressure (BP) responses to exercise. As older adults with lowest handgrip strength also have lowest BP at rest, those with dynapenia may experience attenuated BP responses during physical activity. The purpose of this study was to test the hypothesis that dynapenic older adults would exhibit lower BP response to post-exercise muscle ischemia (PEMI).
Brachial and aortic systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP) were measured in older adults (age, 80 ± 5 y) with dynapenia (n = 16) and non-dynapenia (n = 9) at rest and during PEMI following 2 min of isometric handgrip exercise at 30% maximal voluntary contraction. Walking speed was assessed by an 8-foot (2.44 m) walk course.
Increases in aortic SBP (11 ± 2 vs. 23 ± 6 mm Hg, p = .03), DBP (6 ± 2 vs.14 ± 4 mm Hg, p = .04), and MAP (8 ± 1 vs. 17 ± 5 mm Hg, p = .02) were lower in dynapenic compared to non-dynapenic adults. Aortic MAP (r = 0.52, p < .05) response to PEMI was correlated with MVC in dynapenic adults. Gait speed was correlated with aortic DBP response to PEMI (r = 0.698, p = .05) in non-dynapenic adults.
Our findings indicate that aortic DBP response to muscle metaboreflex activation is attenuated in older adults with dynapenia. Normal aortic DBP response during metaboreflex activation may positively affect walking performance in non-dynapenic older adults.
低肌肉力量（dynapenia）是与年龄相关的肌肉质量和力量丧失或低行走速度的特征。新证据表明，肌肉力量对运动时的血压（BP）反应有积极影响。由于握力最低的老年人在休息时的血压也最低，因此 dynapenic 老年人在进行体育活动时可能会出现血压反应减弱的情况。本研究的目的是检验 dynapenic 老年人在运动后肌肉缺血（PEMI）时血压反应较低的假设。
在 dynapenia（n=16）和非 dynapenia（n=9）老年人中，在进行 30%最大自主收缩等长握力运动 2 分钟后，测量肱动脉和主动脉收缩压（SBP）、舒张压（DBP）和平均动脉压（MAP），并在 PEMI 期间进行休息。通过 8 英尺（2.44 米）步行测试评估行走速度。
与非 dynapenia 成年人相比，dynapenia 成年人的主动脉 SBP（11±2 对 23±6mmHg，p=0.03）、DBP（6±2 对 14±4mmHg，p=0.04）和 MAP（8±1 对 17±5mmHg，p=0.02）的升高幅度较低。dynapenic 成年人 PEMI 时的主动脉 MAP（r=0.52，p<0.05）反应与 MVC 相关。非 dynapenia 成年人的行走速度与 PEMI 时主动脉 DBP 反应相关（r=0.698，p=0.05）。
我们的发现表明，dynapenia 老年人的肌肉代谢反射激活时的主动脉 DBP 反应减弱。代谢反射激活时的正常主动脉 DBP 反应可能会对非 dynapenia 老年人的行走表现产生积极影响。
