Department of Biology, Colgate University, Hamilton, New York, USA.
J Exp Zool A Ecol Integr Physiol. 2024 Jun;341(5):606-614. doi: 10.1002/jez.2809. Epub 2024 Mar 21.
Regulation of internal body temperature (T), or thermoregulation, is an evolutionarily conserved trait that places demand on basal metabolic rate of endothermic animals. Across species, athletes generate increased quantities of heat in comparison to their nonathletic counterparts and, therefore, must mediate physiological unbalance by upregulating the effectiveness of their heat dissipation abilities. Canine athletes are no exception to this phenomenon, however, with literature denoting body temperatures lower than nonathletic canines, it is clear they must possess adaptations to mitigate this demand. With VO max measurements of more than 200 mL/kg/min in sled dogs with mild training to 300 mL/kg/min in highly trained animals, sled dogs are a prime example of athleticism in canines. Seeking to determine correlations between T and body mass, morphology, and age of canine athletes, core body temperature (T) was measured with an instant ear thermometer, using T as a correlate before and after a 2-mile run. In addition, we employed thermal imaging analysis to capture body-wide heat dissipation patterns in sled dogs, and focused on thermal variation of mouth (T), nose (T), and eyes (T). Furthermore, we looked at correlations between thermal variability across these four tissues and head morphology of each dog. T was consistently the highest temperature across all tissues measured, with a 1.5°C increase between pre- to postexercise (p < 0.001). Thermal imaging revealed significant positive correlations between T and body mass 15 min postexercise (p = 0.0023) as well as significantly negative correlations between T and body mass at before exercise (p = 0.0468), T and nose length after run (p = 0.0076), and T and nose length after run (p = 0.0110). As body temperature rises during exercise, it becomes increasingly important to regulate blood flow throughout the body to supply working tissues with oxygen. This demand is offset by the role of the snout in evaporative cooling through panting, functioning as a prime location for heat dissipation and therefore maintaining significant relationships with many other vascularized tissues.
体温（T）调节是一种进化上保守的特征，它对内温动物的基础代谢率提出了要求。在不同物种中，与非运动员相比，运动员会产生更多的热量，因此必须通过提高散热能力的有效性来调节生理失衡。犬类运动员也不例外，然而，文献表明犬类运动员的体温低于非运动员，很明显，它们必须适应这种需求。雪橇犬的 VO max 测量值在轻度训练的犬中超过 200 mL/kg/min，在高度训练的动物中高达 300 mL/kg/min，是犬类运动能力的一个很好的例子。为了确定犬类运动员的体温（T）与体重、体型和年龄之间的相关性，我们使用即时耳温计测量核心体温（T），并在 2 英里跑步前后使用 T 作为相关指标。此外，我们还采用热成像分析来捕捉雪橇犬全身的散热模式，并专注于口（T）、鼻（T）和眼（T）的热变化。此外，我们还研究了这四个组织之间的热变异性与每只狗的头部形态之间的相关性。T 在所有测量的组织中都是最高的温度，运动前后温度升高了 1.5°C（p < 0.001）。热成像显示，运动后 15 分钟 T 与体重呈显著正相关（p = 0.0023），运动前 T 与体重呈显著负相关（p = 0.0468），运动后 T 与鼻长呈显著负相关（p = 0.0076），运动后 T 与鼻长呈显著负相关（p = 0.0110）。随着运动过程中体温的升高，调节全身血液流量以向工作组织供氧变得越来越重要。这种需求通过鼻子在喘气时的蒸发冷却作用来抵消，鼻子是散热的主要部位，因此与许多其他血管化组织保持着显著的关系。
