Youngstedt S D, Dishman R K, Cureton K J, Peacock L J
Department of Exercise Science, University of Georgia, Athens 30602.
J Appl Physiol (1985). 1993 Feb;74(2):825-31. doi: 10.1152/jappl.1993.74.2.825.
We tested the thermogenic hypothesis that reductions in blood pressure and self-reported state anxiety and altered brain electrocortical (electroencephalographic, EEG) activity after acute exercise are due to increased body temperature. Eleven fit [cycle peak O2 consumption (VO2peak) = 57 +/- 5.8 ml.kg-1 x min-1] males (26 +/- 5.8 yr) were randomly assigned to four 20-min conditions in a within-subjects counterbalanced design: 1) thermoneutral (32-35 degrees C) or 2) cold (18-23 degrees C) cycling at 70% VO2peak, 3) passive warm water exposure (39-41 degrees C), and 4) quiet rest (60 dB below ambient; 22 +/- 1 degrees C). All exercise testing was conducted in shoulder-deep water. Esophageal temperature increased equally during thermoneutral cycling (+1.45 +/- 0.05 degrees C) and passive heating (+1.51 +/- 0.06 degrees C), was blunted during cold cycling (+0.40 +/- 0.12 degrees C), and was unchanged at rest. Mean radial arterial pressure (MAP), self-reported state anxiety (State-Trait Anxiety Inventory, STAI), and spontaneous occipital (O1 + O2) and photostimulated temporal (T5 + T6) surface EEG activity (10-20 system) in theta (4-8 Hz), alpha (9-13 Hz), and beta (14-40 Hz) frequency bands were assessed 5 min pre- and 10-15 and 20-25 min postcondition and analyzed in 4- (condition) by-3 (time) repeated-measures analysis of variance (P < 0.05). Results showed a condition-by-time interaction for MAP, which decreased from pre- to 15 min postcondition for thermoneutral cycling (81 +/- 2 to 73 +/- 2.7 mmHg) and passive heating (86 +/- 2.5 to 74 +/- 1.4 mmHg) and persisted at 25 min postcondition.(ABSTRACT TRUNCATED AT 250 WORDS)
急性运动后血压降低、自我报告的状态焦虑减轻以及大脑皮层电活动（脑电图，EEG）改变是由于体温升高所致。11名健康男性（平均年龄26±5.8岁，自行车峰值耗氧量[VO2peak]=57±5.8毫升·千克⁻¹·分钟⁻¹）采用受试者内平衡设计，被随机分配到四种20分钟的条件下：1）热中性环境（32 - 35摄氏度）或2）冷环境（18 - 23摄氏度），以70%VO2peak的强度骑行，3）被动温水暴露（39 - 41摄氏度），4）安静休息（比环境噪音低60分贝；22±1摄氏度）。所有运动测试均在齐肩深的水中进行。食管温度在热中性骑行（升高1.45±0.05摄氏度）和被动加热（升高1.51±0.06摄氏度）过程中升高幅度相同，在冷骑行过程中升高幅度较小（0.40±0.12摄氏度），在休息时无变化。在每种条件前5分钟、条件后10 - 15分钟和20 - 25分钟评估平均桡动脉压（MAP）、自我报告的状态焦虑（状态 - 特质焦虑量表，STAI）以及自发枕叶（O1 + O2）和光刺激颞叶（T5 + T6）表面EEG活动（10 - 20系统）在θ（4 - 8赫兹）、α（9 - 13赫兹）和β（14 - 40赫兹）频段的情况，并通过4（条件）×3（时间）重复测量方差分析进行分析（P < 0.05）。结果显示MAP存在条件×时间交互作用，热中性骑行（从条件前的81±2降至条件后15分钟的73±2.7毫米汞柱）和被动加热（从86±2.5降至74±1.4毫米汞柱）时，MAP从条件前到条件后15分钟降低，并在条件后25分钟持续降低。（摘要截断于250字）
