Anaerobic And Cardiovascular Responses To Solo And Team Live Firefighter Rescue

The ability of a firefighter (FF) to perform live fire rescue operations in the field is an imperative skill; however, the physiological demands associated with solo or team live fire rescues (LR) have not been thoroughly explored. PURPOSE: To compare physiological responses of FF recruits during solo or team LR. METHODS: 20 FF recruits (sex: 18 M/2F; age: 22.9 ± 5.5 y) performed a LR in two rotations, one solo LR and one team LR, the order of which was randomized into rotation 1 (R1) or 2 (R2), while carrying an extra 18-22 kg with full turnout gear and Self-Contained Breathing Apparatus. Heart rate (HR) was measured continuously with chest-strap HR monitors, and lactate was measured via capillary finger prick at 3 time points: baseline, after R1, and after R2. Average HR (HRavg, expressed as a percentage of age-predicted maximum HR [HRmax]) and percentage of time spent in high, moderate, and low HR zones (e.g., >85%, 65-84%, <65% of HRmax, respectively), were calculated per rotation. Data were analyzed with a repeated-measures ANOVA and paired samples t-test for within group analysis of HR variables and lactate concentration. RESULTS: A significant effect of condition (p < 0.05) was found for lactate, with solo LR having a higher lactate (7.1 ± 2.2 mmol/L) than team LR (4.1 ± 1.8 mmol/L),with no effect of time or time × condition. There was a significant effect of time for HRavg, and for time spent in the highest (>85% HRmax) and lowest (<65% HRmax) HR zones (p < 0.05). R2 elicited a higher HRavg (MD: 10.5 ± 13.8%) than R1, more time spent in the highest HR zone (MD:15.6 ± 22.2%), and less time spent in the lowest HR zone (MD: 8.9% ± 17.4%) respectively (p < 0.05 for all). A significant effect of condition emerged for time spent in the lowest HR zone, where team LR spent less time in the lowest HR zone (1.2% ± 1.1%) than solo LR (17.1% ± 12.2%, p < 0.001). CONCLUSION: Solo FF LR demands more sustained anaerobic effort, as shown by elevated lactate levels, while team FF LR appears to require longer periods of sustained higher intensity efforts, demonstrated by less time spent in the lowest HR zone. These findings highlight the differing physiological demands of solo versus team LR, both eliciting high but distinct patterns of cardiovascular strain.