Acute Cardiovascular Effects of Firefighting and Active Cooling During Rehabilitation

Abstract

Objectives To determine the cardiovascular and hemostatic effects of fire suppression and post-exposure active cooling. Methods Forty-four firefighters were evaluated prior to and after a 12 minute live-fire drill. Next, 50 firefighters undergoing the same drill were randomized to post-fire forearm immersion in 10°C water or standard rehabilitation. Results In the first study, heart rate and core body temperature increased and serum C-reactive protein decreased but there were no significant changes in fibrinogen, sE-selectin or sL-selectin. The second study demonstrated an increase in blood coagulability, leukocyte count, factors VIII and X, cortisol and glucose, and a decrease in plasminogen and sP-selectin. Active cooling reduced mean core temperature, heart rate and leukocyte count. Conclusions Live-fire exposure increased core temperature, heart rate, coagulability and leukocyte count; all except coagulability were reduced by active cooling.

Optimizing Cold Water Immersion for Exercise-Induced Hyperthermia

“…The current observation should not be viewed as a refutation of forearm/hand CWI as an effective rehabilitation modality because there are other associated benefits (8,56,65). Yet, insufficient published evidence supports that forearm/hand CWI could yield desirable rapid cooling.…”

Characterizing a Firefighter’s Immediate Thermal Environment in Live-Fire Training Scenarios

“…Some studies have utilized training drills with environmental temperatures less than 100°C in a live-fire burn structure to simulate fire ground activities [18][19][20][21][22]. More commonly, research groups have used a treadmill protocol in a temperature-controlled ( 25°C to 50°C) room [23][24][25][26][27][28].…”

Cooling intervention studies among outdoor occupational groups: A review of the literature

“…Forearm water immersion for 15 min was shown to be better at decreasing core body temperature and HR after fire drills compared to the other interventions examined. 21,[36][37][38] however, the guidelines for cooling are not specific. 29 Nonetheless, the adoption by fire agencies of NFPA standard 1584 is a commitment by the fire agency to protect its workforce and mitigate the negative health effects of occupational heat stress.…”

“…After a 12-min live-fire drill (190-309°C), 50 firefighters were randomized to either standard rehabilitation procedure of resting in the shade (33°C, RH 33%) and drinking cool beverages ad libitum for 15-min or to the intervention group that included standard rehabilitation procedure and forearm immersion in 10°C water. 37 Core temperature was monitored with an ingestible sensor and HR with a chest strap monitor. In another multi-intervention study, firefighters conducted two 20-min simulated search and rescue drills in 105°C climatic chamber.…”