Abstract：
This study investigated the impact of long-term heat acclimation (HA) training on mouse thermoregulation, metabolism, and running performance in temperate (T) and hot (H) environments. Male Swiss mice were divided into 1) Sedentary (SED) mice kept in T (22 °C; SED/T), 2) Endurance Trained mice (ET, 1 h/day, 5 days/week, 8 weeks, 60 % of maximum speed) in T (ET/T), 3) SED kept in H (32 °C; SED/H), and 4) ET in H (ET/H). All groups performed incremental load tests (ILT) in both environments before (pre-ET) and after four and eight weeks of ET. In the pre-ET period, H impaired (∼30 %) performance variables (maximum speed and external work) and increased (1.3 °C) maximum abdominal body temperature compared with T. In T, after four weeks, although ET/H exercised at a lower (∼30 %) absolute intensity than ET/T, performance variables and aerobic power (peak oxygen uptake, VO2peak) were similarly increased in both ET groups compared with SED/T. After eight weeks, the external work was higher in both ET groups compared with SED/T. Only ET/T significantly increased VO2peak (∼11 %) relative to its pre-ET period. In H, only after eight weeks, both ET groups improved (∼19 %) maximum speed and reduced (∼46 %) post-ILT blood lactate concentrations compared with their respective pre-ET values. Liver glycogen content increased (34 %) in both ET groups and SED/H compared with SED/T. Thus, ET/H was performed at a lower absolute intensity but promoted similar effects to ET/T on metabolism, aerobic power, and running performance. Our findings open perspectives for applying HA training as part of a training program or orthopedic and metabolic rehabilitation programs in injured or even obese animals, reducing mechanical load with equivalent or higher physiological demand.
摘要：
这项研究调查了长期热适应（HA）训练对小鼠体温调节的影响，新陈代谢，和运行性能在温度（T）和热（H）环境。雄性瑞士小鼠分为1）保持在T（22°C;SED/T）中的久坐（SED）小鼠，2）经过训练的小鼠（ET，1小时/天,5天/周,8周,最大速度的60％）在T（ET/T）中，3)SED保持在H(32°C;SED/H),和4)在H中的ET(ET/H)。在ET之前（ET之前）以及ET的四周和八周之后，所有组都在两种环境中进行了增量负载测试（ILT）。在ET前期，与T相比，H受损（〜30％）性能变量（最大速度和外部功）并增加（1.3°C）最大腹部体温。四周后，尽管ET/H的绝对强度比ET/T低(~30%)，性能变量和有氧功率(峰值摄氧量，与SED/T相比，两个ET组的VO2peak）相似。八周后,与SED/T相比，两个ET组的外部工作量均较高。相对于ET前期，只有ET/T显著增加了VO2peak(~11%)。在H,八周后,与各自的ET前值相比，两个ET组均提高了（〜19％）最大速度，并降低了（〜46％）ILT后血乳酸浓度。与SED/T相比，ET组和SED/H的肝糖原含量均增加（34％）。因此，ET/H在较低的绝对强度下进行，但促进了与ET/T相似的代谢效果，有氧力量,和运行性能。我们的发现为在受伤甚至肥胖的动物中应用HA训练作为训练计划或骨科和代谢康复计划的一部分开辟了前景。降低机械负荷与同等或更高的生理需求。
