Psychophysiological responses of firefighters to day and night rescue interventions

This study aimed 1) to assess the psychophysiological responses throughout a rescue intervention performed during the day and at night and 2) to determine if a vibrating alarm influences these psychophysiological responses at night. Sixteen male firefighters completed a simulated intervention under three different conditions: 1) during the day with a sound alarm signal (Day_SA), 2) during the night with a sound alarm signal (Night_SA), 3) during the night with a vibrating alarm signal (Night_VA). Cardiovascular and psychological stress were recorded throughout the interventions. During the alarm signal, HR reactivity was greater in Night_SA than in Day_SA (p < 0.01). Parasympathetic reactivation and self-confidence were significantly lower in Night_SA than in Day_SA (p < 0.05). HR reactivity was decreased in Night_VA in comparison to Night_SA (p < 0.05). Overall, the rescue intervention had a greater impact on the psychophysiological variables during the night than during the day, and the type of alarm had a minor effect.