Effectiveness of a field-type liquid cooling vest for reducing heat strain while wearing protective clothing

This study examined the effectiveness of a field-tmie liquid cooling vest (LCV) worn underneath an impermeable protective suit on heat strain during walking. Eight men walked for 60 min at a moderate speed (3.0 km/h) wearing the suit in a warm environment (33 degrees C, 60% relative humidity) without (control, CON) or with the LCV. A smaller increase in rectal temperature was recorded in participants in the LCV than in the CON condition (37.6 +/- 0.1 degrees C vs. 37.9 +/- 0.1 degrees C, p<0.05). Walking while wearing the LCV reduced the level of physiological heat strain, as measured by the mean skin temperature (35.5 +/- 0.1 degrees C vs. 36.3 +/- 0.1 degrees C), chest sweat rate (13.5 +/- 3.0 mg/cm(2)/h vs. 16.6 +/- 3.8 mg/cm(2)/h), chest cutaneous vascular conductance (349 t 88% vs. 463 +/- 122%), body weight loss (0.72 +/- 0.05% vs. 0.93 +/- 0.06%), and heart rate (101 +/- 6 beats/min vs. 111 +/- 7 beats/min) (p<0.05, for all comparisons). These changes were accompanied by a decrease in thermal sensation and discomfort. These results suggest that a field-type LCV attenuates exertional heat strain while wearing impermeable protective clothing.