Pre-shift fluid intake : Effect on physiology, work and drinking during emergency wildfire fighting
- Authors: Raines, Jenni , Snow, Rodney , Petersen, Aaron , Harvey, Jack , Nichols, David , Aisbett, Brad
- Date: 2011
- Type: Text , Journal article
- Relation: Applied Ergonomics Vol.43, no.3 (2011), p.532-540
- Full Text: false
- Reviewed:
- Description: Wildfire fighters are known to report to work in a hypohydrated state, which may compromise their work performance and health. Purpose: To evaluate whether ingesting a bolus of fluid before the shift had any effect on firefighters' fluid consumption, core temperature, or the time they spent in high heart rate and work activity zones when fighting emergency wildfires. Methods: Thirty-two firefighters were divided into non-bolus (AD) and pre-shift drinking bolus (PS, 500 ml water) groups. Results: Firefighters began work hypohydrated as indicated by urine colour, specific gravity and plasma osmolality (Posm) results. Post-shift, firefighters were classified as euhydrated according to Posm and hypohydrated by urinary markers. No significant differences existed between the drinking groups in pre- or post-shift hydration status, total fluid intake, activity, heart rate or core temperature. Conclusion: Consuming a bolus of fluid, pre-shift provided no benefit over non-consumption as both groups had consumed equivalent ad libitum volumes of fluid, 2.5 h into the shift. No benefits of bolus consumption were observed in firefighter activity, heart rate response or core temperature response across the shift in the mild weather conditions experienced. Ad libitum drinking was adequate to facilitate rehydration in firefighters upon completion of their emergency firefighting work shift. © 2011 Elsevier Ltd and The Ergonomics Society.
The effect of prescribed fluid consumption on physiology and work behavior of wildfire fighters
- Authors: Raines, Jenni , Snow, Rodney , Petersen, Aaron , Harvey, Jack , Nichols, David , Aisbett, Brad
- Date: 2013
- Type: Text , Journal article
- Relation: Applied Ergonomics Vol. 44, no. 3 (2013), p. 404-413
- Full Text: false
- Reviewed:
- Description: The purpose of this study was to examine 1) wildfire fighters' ability to consume the prescribed fluid volume (1200 mL h-1), 2) the effect of fluid intake on plasma sodium and hydration, and 3) the effect of fluid intake on firefighters' heart rate, core temperature and activity during emergency suppression shifts. Methods: Thirty-four firefighters were divided into ad libitum (AD, n = 17) and prescribed (PR, n = 17) drinking groups. Results: PR drinkers did not meet the prescribed fluid target, yet consumed over double the volume of AD drinkers. No differences between groups in plasma sodium or hydration were noted. PR drinking resulted in lower core temperature between 2 and 6 h. This did not coincide with reduced cardiovascular strain, greater work activity or larger distances covered when compared to AD drinkers. Conclusion: Extra fluid consumption (above AD) did not improve firefighter activity or physiological function (though PR firefighters core temperature was lower earlier in their shift). Firefighter can self-regulate their fluid consumption behavior and work rate to leave the fireground euhydrated. © 2012 Elsevier Ltd and The Ergonomics Society.