Personal Protective Equipment Immediately Alters the Core–Skin Temperature Gradient in Recruit Firefighters

The purpose of this study was to quantify the degree to which personal protective equipment (PPE) affects the core–skin temperature gradient in nine recruit firefighters attending fire academy. Participants wore a chest monitor and ingested a pill to continually measure skin and core temperature, respectively. PPE status was defined as periods during which participants were wearing full PPE (ON) and not wearing PPE (OFF). During the study, participants transitioned between PPE ON to PPE OFF seven times. These transition timepoints, defined as paired two-minute averages collected immediately before (PPE OFF) and shortly after (PPE ON) donning PPE, were analyzed to examine the immediate effects of PPE use. Factorial repeated-measures ANOVAs were used to assess the effects of PPE status, time, and their interaction on temperature gradient, core temperature, and skin temperature. There was a significant interaction effect on the temperature gradient (p < 0.001), with higher gradients in the OFF condition compared to ON at timepoints 2–7. A significant interaction was observed for skin temperature with higher values in ON than OFF for timepoints 2–7 as well. There was no interaction (p = 0.445) or main effect of PPE status (p = 0.906) for core temperature. This study demonstrates that adding PPE significantly reduced the core–skin temperature gradient in recruit firefighters, largely due to increases in skin temperature.