Cooling strategies for firefighters: Effects on physiological, physical, and visuo-motor outcomes following fire-fighting tasks in the heat

Wilderness First Responder Medical Clearance - A Scoping Review with Recommendations

BACKGROUND AND PURPOSE

Due to environmental extremes, as well as the nature of the work itself, wilderness first responders are at risk of incurring medical events in the line of duty. There currently do not exist standardized and scientifically supported methods to screen for a wilderness first responder's risk of incurring a medical event.

METHODS

We performed multiple scoping reviews using PubMed and CINAHL. The reviews covered six medical screening criteria based on previous recommendations from the National Fire Protection Association (NFPA) and the US Forest Service, and we grouped our reviews into two categories: articles that addressed objective screening criteria, and articles that addressed subjective findings with the first responder.

RESULTS

Of the objective criteria, our reviews identified 21 articles addressing the ability to screen for risk of incurring a medical event by evaluation of a first responder's heart rate, 12 by blood pressure assessment, and 56 by assessment of body temperature. Of the subjective criteria we identified 19 articles focused on self-assessment, 34 articles on the use of standardized tools to assess for fatigue and sleepiness, and two articles on assessment of a first responder's urine to determine level of dehydration. We also identified seven additional articles through a hand search. Overall, there were 151 articles identified in our scoping reviews. These articles were largely of low quality, consisting mostly of case series without comparison groups.

CONCLUSION

There is a dearth of high-quality research into the medical assessment of first responders. We recommend that this paper, and measures discussed within it, be used as a starting point in the development of an evidence-based assessment protocol for wilderness first responders. We also recommend the development of a national database of medical events incurred by wilderness first responders to facilitate higher-quality research of screening protocols in this community.

Heart rate dynamics during a simulated fireground test: The influence of physical characteristics and fitness1

BACKGROUND

Firefighting is a physiologically demanding occupation and there is a need to evaluate physical and fitness characteristics that are related to attenuated physiological stress during fireground tasks. Previous studies have not measured associations between heart rate responses during simulated fireground tasks with a standardized work rate.

OBJECTIVE

The purpose of this study was to examine associations between heart rate during a standardized pace simulated fireground test (SFGT) and heart rate recovery and variability following the SFGT. In addition, this study sought to evaluate associations between heart rate measures versus physical and fitness characteristics in structural firefighter recruits.

METHODS

Twenty-one fire academy recruits performed a standardized pace SFGT while mean heart rate reserve (HRRes) during the SFGT, change in heart rate variability from rest to post-SFGT (LnRMSSDRest-Post), and 60-second post-SFGT heart rate recovery (HRR60) were measured. Regression analyses were conducted between HRRes, LnRMSSDRest-Post and HRR60 and between heart rate measures versus physical and fitness characteristics while accounting for differences in SFGT completion time.

RESULTS

HRRes was associated with LnRMSSDRest-Post, but not HRR60. Height and pull-ups explained most of the variance in HRRes, height explained most of the variance in LnRMSSDRest-Post and push-ups and 1.5-mile run explained most of the variance in HRR60.

CONCLUSION

Greater cardiovascular stress during fireground tasks is associated with greater depression of post-SFGT heart rate variability, but not heart rate recovery. Physical and fitness characteristics are important to consider in relation to firefighters' ability to cope with physical stress on the fireground.

Clinical Evaluation of Exercise-Induced Physiological Changes in Military Working Dogs (MWDs) Resulting from the Use or Non-Use of Cooling Vests during Training in Moderately Hot Environments

Simple Summary

A cooling vest is a clothing article especially designed to reduce body temperature and make exposure to heat in hot climates or environments more bearable. Such cooling vests can be of significant help to military working dogs (MWDs) in high-temperature regions. Dogs performing scent-detection tasks could benefit from the use of a cooling vest, if proven useful, by reducing the risk of heat stroke and olfactory fatigue. As different models of cooling vests are available for dogs, our aim was to compare wearing nothing versus two different models of cooling vests in a homogenous dog population during physical exercise (moderate-intensity running). We observed that the evaporative cooling waistcoat performed best. In conclusion, the waistcoats improve the cooling of the dogs during and after exercise, and differences between the two garment models exist.

Abstract

Nose work with military working dogs (MWDs) in warmer-than-usual areas has led us to look for new tools to reduce both heat stress and the risk of heat stroke. One of the different strategies to manage heat stress is the use of cooling vests, such as those used in humans. The aim was to assess three cooling conditions (using two different cooling vests during exercise and the non-use of such garments) by measuring core body temperature, systemic blood pressure and pulse rate before and after the exercise (moment: four measurement times) in military dogs of the I Military Police Battalion (in Valencia, Spain). All dogs were evaluated under all three conditions during the three days of the study. Significant differences were observed between condition, moment, and the interaction of these two factors, in relation to core body temperature and pulse rate. Therefore, the use of an evaporative cooling vest may further be useful as a routine thermal control and conditioning measure in MWDs.