| Heat acclimation program effects on rectal temperature and heart rate during walks in the heat wearing structural fire protective ensemble (FE) were examined. On six consecutive days, male subjects (N = 7) walked 30 minutes on a treadmill (46--53% V˙O2peak) within a 40 +/- 2°C, 20--22% r.h. environment, wearing FE. Rectal (Trec) mean skin (Tsk), and rectal-skin temperature gradient (T rec-Tsk), heart rate (HR), oxygen uptake (VO2), minute ventilation (VE), rating of perceived exertion (RPE), rating of thermal discomfort (RTD), sweat rate and Na+ and K+ were assessed daily. Significance (p < 0.05) was determined by one way repeated measures ANOVA. Average heart rate, and daily sweat Na+ and K+ concentrations were the only variables observed to decrease significantly during the six days. These changes however were small and represent a questionable practical benefit. Therefore, a six day heat acclimation program during summer months provides no benefit to work in the heat while wearing FE. |
