Hiura Mikio, Funaki Akio, Shibutani Hirohide, Takahashi Katsumi, Katayama Yoichi
Center for Brain and Health Sciences, Aomori University, Aomori, Japan.
Faculty of Sociology, Aomori University, Aomori, Japan.
Front Physiol. 2023 Jul 25;14:1165939. doi: 10.3389/fphys.2023.1165939. eCollection 2023.
The present study used near-infrared spectroscopy to investigate the relationships between cerebral oxygen metabolism and perfusion in the prefrontal cortex (PFC) during exercises of different intensities. A total of 12 recreationally active men (age 24 ± 6 years) were enrolled. They performed 17 min of low-intensity exercise (ExL), followed by 3 min of moderate-intensity exercise (ExM) at constant loads. Exercise intensities for ExL and ExM corresponded to 30% and 45% of the participants' heart rate reserve, respectively. Cardiovascular and respiratory parameters were measured. We used near-infrared time-resolved spectroscopy (TRS) to measure the cerebral hemoglobin oxygen saturation (ScO) and total hemoglobin concentration ([HbT]), which can indicate the cerebral blood volume (CBV). As the cerebral metabolic rate for oxygen (CMRO) is calculated using cerebral blood flow (CBF) and ScO, we assumed a constant power law relationship between CBF and CBV based on investigations by positron emission tomography (PET). We estimated the relative changes in CMRO (rCMRO) and CBV (rCBV) from the baseline. During ExL and ExM, the rate of perceived exertion was monitored, and alterations in the subjects' mood induced by exercise were evaluated using the Profile of Moods Scale-Brief. Three minutes after exercise initiation, ScO decreased and rCMRO surpassed rCBV in the left PFC. When ExL changed to ExM, cardiovascular variables and the sense of effort increased concomitantly with an increase in [HbT] but not in ScO, and the relationship between rCMRO and rCBV was dissociated in both sides of the PFC. Immediately after ExM, [HbT], and ScO increased, and the disassociation between rCMRO2 and rCBV was prominent in both sides of the PFC. While blood pressure decreased and a negative mood state was less prominent following ExM compared with that at rest, ScO decreased 15 min after exercise and rCMRO surpassed rCBV in the left PFC. Dissociated coupling between cerebral oxidative metabolism and perfusion in the PFC was consistent with the effort required for increased exercise intensity and associated with post-exercise hypotension and altered mood status after exercise. Our result demonstrates the first preliminary results dealing with the coupling between cerebral oxidative metabolism and perfusion in the PFC using TRS.
本研究采用近红外光谱技术，调查不同强度运动期间前额叶皮质（PFC）的脑氧代谢与灌注之间的关系。共招募了12名有休闲运动习惯的男性（年龄24±6岁）。他们先进行了17分钟的低强度运动（ExL），然后在恒定负荷下进行3分钟的中等强度运动（ExM）。ExL和ExM的运动强度分别相当于参与者心率储备的30%和45%。测量了心血管和呼吸参数。我们使用近红外时间分辨光谱（TRS）来测量脑血红蛋白氧饱和度（ScO）和总血红蛋白浓度（[HbT]），后者可指示脑血容量（CBV）。由于脑氧代谢率（CMRO）是通过脑血流量（CBF）和ScO计算得出的，基于正电子发射断层扫描（PET）的研究，我们假定CBF和CBV之间存在恒定的幂律关系。我们估计了CMRO（rCMRO）和CBV（rCBV）相对于基线的相对变化。在ExL和ExM期间，监测主观用力程度，并使用简版情绪状态量表评估运动引起的受试者情绪变化。运动开始三分钟后，左侧PFC的ScO下降，rCMRO超过rCBV。当ExL转变为ExM时，心血管变量和用力感随着[HbT]的增加而同时增加，但ScO未增加，并且PFC两侧的rCMRO和rCBV之间的关系出现分离。ExM结束后立即出现，[HbT]和ScO增加，并且PFC两侧rCMRO2和rCBV之间的分离很明显。与静息时相比，ExM后血压下降且负面情绪状态不那么明显，运动后15分钟ScO下降，左侧PFC的rCMRO超过rCBV。PFC中脑氧化代谢与灌注之间的分离耦合与运动强度增加所需的努力一致，并与运动后低血压和运动后情绪状态改变有关。我们的结果展示了使用TRS处理PFC中脑氧化代谢与灌注之间耦合关系的首个初步结果。
