Physiological responses and parasympathetic reactivation in rescue interventions: The effect of the breathing apparatus

This study aimed to assess the effect of wearing a breathing apparatus during a simulated rescue intervention on psychophysiological responses and parasympathetic reactivation of firefighters. Thirty‐four firefighters participated in this study which consisted of four experimental sessions conducted randomly: a maximal fitness test and three rescue interventions performed (a) with personal protective clothing ( PPC ); (b) with PPC and the full self‐contained breathing apparatus ( SCBA ), including cylinder, full‐face piece, and breathing regulator; and (c) with PPC and only the cylinder of the self‐contained breathing apparatus ( SCBA c). Physiological (heart rate [ HR ], breathing frequency [ BF ]) and perceptual (rating of perceived exertion [ RPE ]) responses were continuously collected during the three rescue interventions. Parasympathetic reactivation was assessed using HR recovery and variability indexes after experimental sessions. HR responses ranged between 63% and 95% of HR max , and BF responses ranged between 22 and 55 breaths/min for the different activity tasks. Parasympathetic reactivation indexes were similar for the rescue interventions but lower than after the intermittent fitness test ( P = 0.016 – P < 0.0001). Mean HR for both SCBA c (83.2 ± 4.1% HR max ) and SCBA (83.1 ± 5.2% HR max ) was higher in comparison with PPC (79.5 ± 5.3% HR max ). RPE was higher for SCBA than for SCBA c which was higher than PPC . Mean BF for SCBA (34 breaths/min) was lower than PPC (40 breaths/min) and SCBA c (43 breaths/min). Based on HR , BF , and RPE , rescue interventions seem to be psychologically and physiologically stressful. Parasympathetic reactivation after PCC , SCBA , and SCBA c suggests that these conditions induce higher cardiac stress than the maximal fitness test. The study showed that SCBA increased psychophysiological perturbations.