Foreman J H, Grubb T L, Benson G J, Frey L P, Foglia R A, Griffin R L
Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, College of Veterinary Medicine, USA.
Equine Vet J Suppl. 1996 Jul(22):85-90. doi: 10.1111/j.2042-3306.1996.tb05035.x.
This study was designed to characterise the acid-base and electrolyte effects of shortening the distance required during steeplechase (Phase B) in the face of hot and humid weather conditions during a treadmill-simulated Speed and Endurance test. Eight conditioned Thoroughbred horses underwent 3 randomised permutations of a standardised exercise test on a high speed treadmill. Each test consisted of trotting at 3.7 m/s for 10 min (Phase A); galloping at 11 m/s (Phase B) for 4 (cool laboratory conditions), 3 (hot and humid), or 2 (hot and humid) min; trotting at 3.7 m/s for 30 min (Phase C); and walking at 1.8 m/s for 10 min (Phase X). The treadmill slope was 4% for trotting and galloping and 0% for walking. Cool versus hot and humid conditions were 20 degrees C and 50-60% relative humidity vs. 26-28 degrees C and 80-85% relative humidity, respectively. Pulmonary artery blood samples were obtained at rest prior to exercise (Rest); at the end of Phases A (A10) and B (B2-4); at 10 (C10), 20 (C20) and 30 (C30) min through Phase C; and at 5 min into Phase X (X5). Additional samples for lactate (LA) and glucose (GLC) analysis were obtained 5 min into Phase C (C5) and at the end of Phase X (X10). Samples were analysed for packed cell volume (PCV), haemoglobin (HB), total plasma protein (TP), sodium (Na), potassium (K), chloride (Cl), anion gap (AG), plasma glucose (GLC) and lactate (LA), pH, PCO2, bicarbonate (HCO3) and base excess (BE). Shortening steeplechase distance by 50% under hot and humid conditions (2 min B) resulted in a consistent return to control measurements (4 min B) only for plasma LA. Changes in PCV, HB, TP, K and Cl were related more to the longer galloping distance in the 4 min B trials than to hot vs. cold laboratory conditions. Alternatively, changes in LA, GLC, pH, PCO2 and AG were more related to hot and humid laboratory conditions than they were to galloping distance. These latter variables, when combined with physical measures such as core temperature, bodyweight loss, point of fatigue on Phase C and recovery heart rates may serve as the best monitors of positive responses in future studies of proposed modifications to Phase C, rather than those variables which were more distance than weather-related.
本研究旨在描述在跑步机模拟的速度和耐力测试中，面对炎热潮湿的天气条件时，缩短障碍赛（阶段B）所需距离对酸碱和电解质的影响。八匹经过训练的纯种马在高速跑步机上进行了3次标准化运动测试的随机排列。每次测试包括以3.7米/秒的速度小跑10分钟（阶段A）；以11米/秒的速度疾驰（阶段B）4分钟（凉爽实验室条件下）、3分钟（炎热潮湿条件下）或2分钟（炎热潮湿条件下）；以3.7米/秒的速度小跑30分钟（阶段C）；以及以1.8米/秒的速度行走10分钟（阶段X）。跑步机小跑和疾驰时的坡度为4%，行走时为0%。凉爽与炎热潮湿条件分别为20摄氏度和相对湿度50 - 60% 与26 - 28摄氏度和相对湿度80 - 85%。在运动前静息状态（休息）、阶段A结束时（A10）和阶段B结束时（B2 - 4）、阶段C的10分钟（C10）、20分钟（C20）和30分钟（C30）以及阶段X开始5分钟（X5）采集肺动脉血样。在阶段C开始5分钟（C5）和阶段X结束时（X10）采集额外的样本用于乳酸（LA）和葡萄糖（GLC）分析。分析样本的血细胞比容（PCV）、血红蛋白（HB）、总血浆蛋白（TP）、钠（Na）、钾（K）、氯（Cl）、阴离子间隙（AG）、血浆葡萄糖（GLC）和乳酸（LA）、pH值、二氧化碳分压（PCO₂）、碳酸氢盐（HCO₃）和碱剩余（BE）。在炎热潮湿条件下将障碍赛距离缩短50%（2分钟B），仅血浆LA出现了一致的恢复到对照测量值（4分钟B）的情况。PCV、HB、TP、K和Cl的变化更多地与4分钟B试验中较长的疾驰距离有关，而非炎热与寒冷的实验室条件。相比之下，LA、GLC、pH值、PCO₂和AG的变化与炎热潮湿的实验室条件关系更大，而非疾驰距离。在未来关于对阶段C提议修改的研究中，这些后一类变量与诸如核心温度、体重减轻、阶段C的疲劳点和恢复心率等身体指标相结合，可能是积极反应的最佳监测指标，而不是那些与距离相关性大于与天气相关性的变量。
