Evaluating Curriculum Sequence On Allostatic Load Biomarkers In Fire Academy Training

Fire academies (FA) consist of rigorous curricula, comprising emergency medical technician (EMT) and fire training (FT), designed to simulate the high-stress situations firefighters encounter on the job. Prolonged stress exposure during FA may impact recruits’ health and performance. Little is known about how training order (TO) within a FA curriculum may influence recruits' stress biomarkers (SB) of allostatic load. Understanding the effect of TO could provide insights to optimizing training. PURPOSE: To evaluate the effect of TO on changes in SB over the course of a FA. METHODS: Data from 34 recruits in two classes at a FA were analyzed over 30 weeks. Classes ran concurrently, Class A began with EMT training prior to FT, Class B followed the reverse order. Daily measures included bodyweight, resting heart rate, breathing rate (BR), blood pressure (BP), urine color, and stress levels. Initial physical fitness (PF) assessments were conducted. T-tests compared baseline PF and SB between classes. An analysis of covariance (ANCOVA) assessed the main effect of TO on SB changes, with baseline levels as covariates. Effect sizes were computed using partial eta-squared (η2), with η2 values of 0.01, 0.06, and 0.14 representing small, medium, and large effects, respectively. RESULTS: Baseline differences were found in urine color and systolic BP (Class A > Class B; p < 0.05). No differences in other SB or PF measures were observed. The ANCOVA revealed no overall differences in SB changes. During FT, a significant effect of class on BR was observed (Class A: x̅ = -1.4 ± 3.9; Class B: x̅ = -0.3 ± 3.4). CONCLUSIONS: TO had limited overall impact on SB changes. Yet, during FT, Class A showed a decrease in BR, while Class B exhibited a small increase. High between-subject variability was observed, with baseline SB levels often predicting changes during the FA. This suggests that individual differences played a substantial role in SB throughout training, potentially overshadowing the effects of TO.