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Physiological responses to repeated heat exposure under equal work load conditions
Renan Augusto Bortolassi de Oliveira1,2, Anderson Caetano Paulo3, Leonardo Farah4
1Ergonomics Laboratory, Federal Technological University of Paraná, Brazil.
Summary
Intermittent heat exposure is more efficient for firefighters than continuous exposure. Monitoring heart rate (HR) and rate pressure product (RPP) helps assess firefighter health during fire suppression activities.
Area of Science:
- Occupational Health
- Environmental Physiology
- Firefighter Safety
Background:
- Firefighting involves significant heat exposure, posing risks to personnel.
- Understanding physiological responses to different heat exposure patterns is crucial for firefighter safety.
Purpose of the Study:
- To compare physiological responses to continuous versus intermittent heat exposure in firefighters.
- To evaluate skin temperature, oxygen saturation, blood pressure, heart rate (HR), heart rate variability (HRV), and rate pressure product (RPP).
Main Methods:
- Sixteen male firefighters participated in two conditions: 30 minutes continuous heat exposure and two 15-minute exposures with 10-minute breaks.
- Physiological parameters including skin temperature, oxygen saturation, blood pressure, HR, HRV, and RPP were monitored.
- Workload was kept constant between the two experimental conditions.
Main Results:
- Intermittent heat exposure resulted in significantly lower percentage changes in HR, mean normal interval, RMSSD, and RPP compared to continuous exposure.
- These findings indicate a reduced physiological strain under intermittent heat conditions.
- Skin temperature and HR were lower during intermittent re-exposure periods.
Conclusions:
- Intermittent heat exposure is an effective strategy for fire suppression activities, reducing physiological stress.
- Rate pressure product (RPP) is a valuable, inexpensive metric for monitoring firefighter cardiac strain between exposures.
- Monitoring RPP alongside skin temperature and HR can enhance firefighter health surveillance during demanding operations.
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