Stress test at 44°C and 80 % of humidity and usefulness of ice suit
Main Article Content
Keywords
Exercise test stress test in the heat, Heat stroke, Physical exertion, Hot temperature, Humidity
Abstract
Objective: to compare the fatigue in a stress test at high temperature and humidity in eight healthy volunteers.
Methods: the time of pedaling in the ergometer cycle was measured to know the exercise´s efficiency at 30 km/h until the volunteers presented exhaustion or their heart frequency increased > 160 beating per minute. A basal test in the tunnel´s ventilation of the Naica mine at 37.5 °C and 40 % of humidity was done. We repeat the stress test at the entrance of the cave, where temperature was 44 °C and 80 % of humidity. We compared using the protector equipment with ice and cold air breathing suit.
Results: the stress test al 44 °C and 80 % of humidity with the protector suit was interrupted al the 75% because of an increase in the heart frequency (> 160 per minute)The exercise time was duplicated in the 62 % and was increased in the 100% on the participants with an average increase of 2.25 times and a rank (1.12-3.3). Statistical Wilcoxon test the differences between the times of stress test with and without equipment alt 44 °C an 80 % of humidity with a Z of 2.52 and a p of .012 was done.
References
Moran S, Heled Y, Still L. Assesment of heat tolerance for postexertional heat stroke individual. Med. Sci Monit 2004;10(6):252-257.
González-Alonso J, Teller C, Andersen SL, Jensen FB, Hyldig T, Nielsen B. Influence of body temperature on the development of fatigue during prolonged exercise in the heat. J. Appl Physiol 1999;86(3):1032-1039.
Choukroun ML, Kays C, Varéne P. Effects of water temperature on pulmonary. Resp Physiol 1989;75(3):255-266.
Zhu M, Ackeman JJ, Sikstanskii AL, Yablonskjy DA. How the body controls brain temperature; the temperature shielding effect of cerebral blood flow. J Appl Physiol 2006; 101(5):1481-1488.
Donoghue AM, Sinclair MJ, Bates GP. Heat exhaustion in a deep underground. Occup Environ Med 2000;57(3): 165-174.
Wexler RK. Evaluation and treatment of heat-related illnesses Am Fam Phys 2002;65(11):2307-2314.
Varghese GM, John G, Thomas K, Abraham OC, Mathai D. Predictors of multi-organ dysfunction in heatstroke. Emerg Med J 2005;22(3):185-187.
Brake DJ, Bates GP. Fluid losses and hydration status of industrial workers. Occup Environ Med 2003;60(2):90-96.
Carter R 3rd, Cheuvront SN, Vernieuw CR, Sawka MN. Hypohydration and prior heat stress exacerbates decreases in cerebral blood flow velocity during standing. J Appl Physiol 2006;101(6):1744-1750.