Grant: Engage Plus Grants Program

Keeping cool during exercise in the heat depends on our sweat glands secreting a thin film of water on our skin, and then having our body's heat evaporate that water. Wearing clothing affects this process in different ways: 1) sweat can soak the clothing, changing how it insulates and protects the body; 2) sweat can be trapped between the skin and clothing, increasing discomfort and slowing sweating rates; and 3) sweat moving to the outer surface of clothing means that some of the heat for evaporation comes from the air rather than the body, making sweating less effective.One ongoing goal in clothing design, therefore, has been to improve sweat movement through clothing while retaining insulation by developing special wicking fabrics. However, a limitation of most current testing protocols with new fabrics is that they are restricted to testing the fabric by itself on a test bench, such as testing the insulation and wicking on a small piece of fabric over a hot plate. Most such tests are also done with dry fabric, which does not represent the clothing in actual use with sweat or condensation. What is missing in industrial testing is the controlled testing of actual clothing worn during exercise. In our initial NSERC Engage collaboration with Mark's, we developed a protocol for testing the sweat transport and thermal performance of cold weather clothing during both exercise and rest in the cold. With this Engage Plus project, we will extendand test this protocol for use with cooling fabrics during exercise and rest in a hot environment. We will measure how much sweat moves within and through different types of hot-weather clothing while subjects are both exercising and resting in the heat. We will then use this data to develop a better understanding of how clothing and sweating affects each other.