Newhouse Douglas, Mihalcin Emily, Lefebvre Karlee, Nucci Mario, Ravanelli Nicholas
School of Kinesiology, Lakehead University, Thunder Bay, Ontario, CANADA.
Northern Ontario School of Medicine University, Thunder Bay, Ontario, CANADA.
Med Sci Sports Exerc. 2024 Dec 1;56(12):2328-2337. doi: 10.1249/MSS.0000000000003527. Epub 2024 Jul 31.
Despite sparse systematic evidence, current exercise heat safety recommendations suggest that antihistamines blunt sweating and increase the risk for heat-related injury during exertional heat stress. The primary purpose of the present study was to examine whether diphenhydramine hydrochloride (DPH), a first-generation antihistamine, affects the sweating, core temperature, and heart rate (HR) response during exertional heat stress using a double-blind randomized crossover design.
On two occasions separated by >48 h, 20 healthy adults (10 females, 23 ± 3 yr, body surface area: 1.9 ± 0.2 m 2 , body mass index: 23.7 ± 2.2 kg·m -2 ) orally consumed either 50 mg of DPH or placebo (PLA), and then rested for 2 h in a climate-controlled room maintained at 30°C and 35% relative humidity (heat index of ~29°C), followed by a 60-min fixed-heat production treadmill walk (6.3 ± 1.0 W·kg -1 ). Whole-body sweat loss, local sweat rate, rectal temperature ( Trec ), and HR were measured.
Whole-body sweat loss was not different between conditions (PLA: 406 ± 78 g, DPH: 396 ± 75 g; P = 0.26, treatment effect: -10 g; 95% confidence interval, -28 to 8). No differences were observed for the onset of sweating (PLA: 13.5 ± 2.4 min, DPH: 13.3 ± 2.7 min; P = 0.79) and steady-state local sweat rate (PLA: 0.83 ± 0.26 mg·cm -2 ·min -1 , DPH: 0.82 ± 0.27 mg·cm -2 ·min -1 ; P = 0.99). No difference in baseline Trec was observed (PLA: 37.09°C ± 0.35°C, DPH: 37.13°C ± 0.33°C; P = 0.68), and the 60-min Δ Trec was not different ( P = 0.99) between PLA (0.83°C ± 0.29°C) and DPH (0.81°C ± 0.30°C). HR was similar at baseline (PLA: 86 ± 13 bpm, DPH: 84 ± 11 bpm; P = 0.30) and end-exercise (PLA: 134 ± 28 bpm, DPH: 132 ± 26 bpm; P = 0.90).
Fifty milligrams of DPH does not modify the sweating, core temperature, and HR response during exertional heat stress in young healthy adults.
尽管系统性证据稀少，但当前的运动热安全建议表明，抗组胺药会抑制出汗，并增加运动热应激期间与热相关损伤的风险。本研究的主要目的是采用双盲随机交叉设计，研究第一代抗组胺药盐酸苯海拉明（DPH）是否会影响运动热应激期间的出汗、核心体温和心率（HR）反应。
20名健康成年人（10名女性，23±3岁，体表面积：1.9±0.2平方米，体重指数：23.7±2.2千克·米-2）在两次间隔超过48小时的情况下，分别口服50毫克DPH或安慰剂（PLA），然后在温度控制在30°C、相对湿度为35%（热指数约为29°C）的气候控制室中休息2小时，随后进行60分钟固定产热的跑步机行走（6.3±1.0瓦·千克-1）。测量全身出汗量、局部出汗率、直肠温度（Trec）和HR。
不同条件下全身出汗量无差异（PLA：406±78克，DPH：396±75克；P=0.26，治疗效果：-10克；95%置信区间，-28至8）。出汗开始时间（PLA：13.5±2.4分钟，DPH：13.3±2.7分钟；P=0.79）和稳态局部出汗率（PLA：0.83±0.26毫克·厘米-2·分钟-1，DPH：0.82±0.27毫克·厘米-2·分钟-1；P=0.99）也无差异。基线Trec无差异（PLA：37.09°C±0.35°C，DPH：37.13°C±0.33°C；P=0.68），PLA（0.83°C±0.29°C）和DPH（0.81°C±0.30°C）之间60分钟的Trec变化也无差异（P=0.99）。HR在基线时相似（PLA：86±13次/分钟，DPH：84±11次/分钟；P=0.30），运动结束时也相似（PLA：134±28次/分钟，DPH：132±26次/分钟；P=0.90）。
50毫克DPH不会改变年轻健康成年人在运动热应激期间的出汗、核心体温和HR反应。
