Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, 01760-5007, USA.
Biophysics and Biomedical Modeling Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, 01760-5007, USA.
J Therm Biol. 2020 May;90:102603. doi: 10.1016/j.jtherbio.2020.102603. Epub 2020 Apr 28.
Military working dogs (MWDs) operate under a wide range of conditions, including hot environments. Predicting how long a MWD can safely work without overheating is important for both health and performance. A Canine Thermal Model (CTM) was developed to predict core temperature (Tc) of MWDs. The CTM calculates heat storage from the balance of heat production from metabolism and heat exchange with the environment. Inputs to the CTM are: meteorological conditions (ambient temperature, relative humidity, solar radiation and wind speed), physical characteristics of the dog (mass, length), and metabolic activity (MET level, estimated from accelerometer data). The CTM was validated against Tc measured in 23 MWDs during training sessions (11.6 ± 5.0 min (mean ± standard deviation), range 4-26 min) in October (24 °C, 52% RH), March (14 °C, 74% RH), or August (28 °C, 64% RH), and 24 kennel MWDs during a standard exercise walk (11.4 ± 3.3 min, range 5.6-18 min) in July (26 °C, 77% RH). The CTM was considered acceptable if predicted Tc was within ±0.5 °C of measured Tc at the end of exercise. Compared to Tc at the end of training sessions (39.8 ± 0.6 °C, range 38.4-41.1 °C) and exercise walks (40.0 ± 0.7 °C, range 38.9-41.4 °C), the CTM-predicted Tc was within ±0.5 °C for 71 of 84 cases (85%) and 19 of 24 cases (79%), respectively. The mean difference between CTM-predicted and measured final Tc during training was -0.04 ± 0.43 °C, with 80 of 84 cases (95%) within the range of ±2 SD (Bland Altman comparison). During exercise walks the mean difference was -0.15 °C ± 0.57, with 23 of 24 cases (96%) within ±2 SD. These results support the use of the CTM to predict Tc of MWDs for the types of physical activities described above.
军犬（MWD）在广泛的条件下工作，包括炎热的环境。预测 MWD 在不过热的情况下可以安全工作多长时间对于健康和性能都很重要。开发了一种犬类热模型（CTM）来预测 MWD 的核心温度（Tc）。CTM 通过新陈代谢产生的热量与环境交换的热量平衡来计算热量储存。CTM 的输入包括：气象条件（环境温度、相对湿度、太阳辐射和风速）、犬的物理特性（质量、长度）和代谢活动（通过加速度计数据估计的 MET 水平）。在 10 月（24°C，52%RH）、3 月（14°C，74%RH）或 8 月（28°C，64%RH）期间，23 只 MWD 在训练期间进行了 Tc 测量（11.6±5.0 分钟（平均值±标准差），范围 4-26 分钟），24 只犬舍 MWD 在 7 月（26°C，77%RH）的标准运动步行中进行了 Tc 测量（11.4±3.3 分钟，范围 5.6-18 分钟）。如果预测 Tc 在运动结束时与测量 Tc 的差值在±0.5°C 以内，则认为 CTM 是可以接受的。与训练结束时的 Tc（39.8±0.6°C，范围 38.4-41.1°C）和运动步行时的 Tc（40.0±0.7°C，范围 38.9-41.4°C）相比，CTM 预测的 Tc 在 71 个案例（85%）和 19 个案例（79%）中，在±0.5°C 以内。在训练过程中，CTM 预测的终末 Tc 与实测终末 Tc 的平均差值为-0.04±0.43°C，84 个案例中有 80 个（95%）在±2SD 范围内（Bland Altman 比较）。在运动步行时，平均差值为-0.15°C±0.57°C，24 个案例中有 23 个（96%）在±2SD 范围内。这些结果支持使用 CTM 来预测上述类型的体力活动中 MWD 的 Tc。
