Ventilated vest and tolerance for intermittent exercise in hot, dry conditions with military clothing.
BACKGROUND
Recent research has focused on developing air-ventilated garments to improve evaporative cooling in military settings. This study assessed a ventilated vest (Vest) in hot (45 degrees C), dry (10% RH) ambient conditions over 6 h of rest and exercise. It was hypothesized that the Vest would lower the thermal strain and increase the amount of exercise done by subjects.


METHODS
Eight healthy heat-acclimated men, wearing combat clothing, body armor, and a 19-kg load in webbing walked on a treadmill at 5 km h(-1) at a 2% incline until rectal temperature (T(rec)) reached 38.5 degrees C. They then rested until T(re) reached 38 degrees C, at which point they recommenced walking. On one occasion the subjects wore a Vest, blowing ambient air around the torso. On the second occasion subjects did not wear the vest (NoVest). Exercise/rest ratio, T(rec), skin temperature (T(sk)), sweat responses, rating of perceived exertion (RPE), and thermal comfort (TC) were measured.


RESULTS
Subjects wearing theVest exercised for significantly longer (18%; 11 min/h) as a percentage of total exposure time, stopped exercise significantly less often [Mean (SD); NoVest: 3 (2) stops; Vest: 1 (2) stops], and maintained significantly lower skin temperature under the body armor [T(chest): NoVest 37.55 (0.51) degrees C; Vest: 35.33 (1.00) degrees C; T(back): NoVest: 36.85 (0.83) degrees C; Vest: 35.84 (0.88) degrees C]. The Vest provided 28 W of cooling during exercise and 73 W when at rest as estimated by thermometry.


CONCLUSIONS
A ventilated vest can provide cooling, and thereby reduce thermal strain and increase exercise done in dry environmental temperatures up to 45 degrees C, without causing skin irritation and discomfort.
Barwood
Martin J
MJ
Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, Hampshire, UK. martin.barwood@port.ac.uk
Newton
Phillip S
PS
Tipton
Michael J
MJ
D000293:Adolescent; D015331:Cohort Studies; D004867:Equipment Design; D005080:Exercise Test; D017079:Exercise Tolerance; D018882:Heat Stress Disorders / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008889:Military Personnel; D011481:Protective Clothing; D055815:Young Adult