Cooling vest worn during active warm-up improves 5-km run performance in the heat

Department of Exercise Science, University of Georgia, Athens, Georgia 30602-6554 Submitted 10 September 2003 ; accepted in final form 4 December 2003 We investigated whether a cooling vest worn during an active warm-up enhances 5-km run time in the heat. Seventeen competitive runners (9 men, maximal oxygen uptake = 66.7 ± 5.9 ml·kg -1 ·min -1 ; 8 women, maximal oxygen uptake = 58.0 ± 3.2 ml·kg -1 ·min -1 ) completed two simulated 5-km runs on a treadmill after a 38-min active warm-up during which they wore either a T-shirt (C) or a vest filled with ice (V) in a hot, humid environment (32°C, 50% relative humidity). Wearing the cooling vest during warm-up significantly ( P < 0.05) blunted increases in body temperature, heart rate (HR), and perception of thermal discomfort during warm-up compared with control. At the start of the 5-km run, esophageal, rectal, mean skin, and mean body temperatures averaged 0.3, 0.2, 1.8, and 0.4°C lower; HR averaged 11 beats/min lower; and perception of thermal discomfort (5-point scale) averaged 0.6 point lower in V than C. Most of these differences were eliminated during the first 3.2 km of the run, and these variables were not different at the end. The 5-km run time was significantly lower ( P < 0.05) by 13 s in V than C, with a faster pace most evident during the last two-thirds of the run. We conclude that a cooling vest worn during active warm-up by track athletes enhances 5-km run performance in the heat. Reduced thermal and cardiovascular strain and perception of thermal discomfort in the early portion of the run appear to permit a faster pace later in the run. body temperature; cardiovascular strain; exercise; running; thermo-regulation Address for reprint requests and other correspondence: S. Á. Arngrímsson, Div. of Sport and Physical Education, Iceland Univ. of Education, Lindarbraut 4, 840 Laugarvatn, Iceland (E-mail: sarngrim{at}khi.is ).