Abstract
The thermal properties of two types of commercially available running apparel (SS : nylon singlet and shorts ; L :spandex/nylon bodysuit) and two bodysuits of newly developed stretchable, water vapour permeable fabrics (B and K) were investigated under ambient conditions of 0° and 25°C, 50% RH. Six male, middle distance runners performed 30 minute runs on a treadmill at a pace requiring approximately 80% of maximum oxygen uptake against a fan generated wind of 4.2m·sec-1. Oxygen uptake kinetics, heart rate, sweating rate, core and skin temperature and perceived exertion were recorded. At 25°C, the K suit retained 23.5 and the B suit retained 9.1 times as much sweat as SS apparel (p≤.01). Both suits became intolerable for running in beyond 22 and 25 minutes, respectively (p≤.01) at the designated speed. However, at 0°C, subject tolerance for all apparels exceeded the criterion running time. In the cool condition the comparatively high air permeability of the L suit resulted in a significantly lower core temperature increase (p≤.035), compared with the other apparels. Even in cool conditions, the K suit retained significantly more sweat than the other apparels (p≤.01). However, subjects favoured the K suit over the B suit due to its lighter weight and greater stretchability. In order to maintain efficient thermoregulation during extended wear in the hotter environment, future running suits should be developed from stretchable materials which have better vapour permeability.
