Mano Jumpei, Saku Keita, Kinoshita Hiroyuki, Mannoji Hiroshi, Kanaya Shigehiko, Sunagawa Kenji
Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan.
Technology Development HQ, OMRON Healthcare Co., Ltd., Kyoto, Japan.
PLoS One. 2021 Mar 18;16(3):e0248428. doi: 10.1371/journal.pone.0248428. eCollection 2021.
The increase of blood pressure (BP) variability (BPV) is recognized as an important additional cardiovascular risk factor in both normotensive subjects and hypertensive patients. Aging-induced atherosclerosis and autonomic dysfunction impair the baroreflex and, in turn, augment 24-hour BPV. In small and large animal experiments, impaired baroreflex steepens the slope of the power spectrum density (PSD) of continuous BP in the frequency range of 0.01 to 0.1 Hz. Although the repeated oscillometric BP recording over 24 hours or longer is a prerequisite to quantify BPV in humans, how the very short-term continuous BP recording reflects BPV remains unknown. This study aimed to evaluate the impact of aging on the very short-term (30-min) BPV in healthy human subjects by frequency analysis.
We recorded continuous BP tonometrically for 30 min in 56 healthy subjects aged between 28 and 85 years. Considering the frequency-dependence of the baroreflex dynamic function, we estimated the PSD of BP in the frequency range of 0.01 to 0.1 Hz, and compared the characteristics of PSD among four age groups (26-40, 41-55, 56-70 and 71-85 years).
Aging did not significantly alter mean and standard deviation (SD) of BP among four age groups. PSD was nearly flat around 0.01 Hz and decreased gradually as the frequency increased. The slope of PSD between 0.01 and 0.1 Hz was steeper in older subjects (71 years or older) than in younger subjects (55 years or younger) (p < 0.05).
Aging steepened the slope of PSD of BP between 0.01 and 0.1 Hz. This phenomenon may partly be related to the deterioration of the baroreflex in older subjects. Our proposed method to evaluate very short-term continuous BP recordings may contribute to the stratification of BPV.
血压（BP）变异性（BPV）增加被认为是正常血压个体和高血压患者中一个重要的额外心血管危险因素。衰老引起的动脉粥样硬化和自主神经功能障碍会损害压力反射，进而增加24小时BPV。在小型和大型动物实验中，受损的压力反射会使连续血压在0.01至0.1赫兹频率范围内的功率谱密度（PSD）斜率变陡。虽然24小时或更长时间的重复示波血压记录是量化人类BPV的前提条件，但极短期连续血压记录如何反映BPV仍不清楚。本研究旨在通过频率分析评估衰老对健康人类受试者极短期（30分钟）BPV的影响。
我们对56名年龄在28至85岁之间的健康受试者进行了30分钟的连续血压记录。考虑到压力反射动态功能的频率依赖性，我们估计了0.01至0.1赫兹频率范围内血压的PSD，并比较了四个年龄组（26 - 40岁、41 - 55岁, 56 - 70岁和71 - 85岁）之间PSD的特征。
衰老并未显著改变四个年龄组之间的血压均值和标准差（SD）。PSD在0.01赫兹左右几乎是平坦的，并且随着频率增加而逐渐下降。71岁及以上的老年受试者在0.0到0.1赫兹之间的PSD斜率比55岁及以下的年轻受试者更陡（p < 0.05）。
衰老使0.01至0.1赫兹之间血压的PSD斜率变陡。这种现象可能部分与老年受试者压力反射的恶化有关。我们提出的评估极短期连续血压记录的方法可能有助于BPV的分层。
