One of the more common terms that is used to describe outdoor gear these days is “breathable.” Whether it’s a pair of shoes, a performance running or hiking shirt, or a rain jacket, that word usually finds its way into marketing materials, product websites, and gear reviews in some way. But just what does “breathable” mean in terms of performance, and why is it something you should be concerend about? Read on for some answers.
Put in the simplest terms possible, breathability refers to a garments ability to pull (or wick) moisture through its fabrics and away from the skin. Fabrics that are breathable tend to be quick drying too, allowing them to help keep the person wearing the article of clothing much more comfortable over the course of their outdoor adventures. This is especially true when they are taking part in particularly active pursuits, such as running, cycling, or climbing. No article of clothing can prevent the wearer from sweating of course, but if that clothing is breathable it can help wick moisture away from their body, and keep them much more comfortable as a result.
Wearing clothing that is breathable when outdoors can aid in regulating temperature too. If a jacket, shirt, or pair of pants isn’t breathable it could end up not only getting wet, but also staying wet for an extended period of time. Wet clothes can be dangerous on the trail, as they can actually lower your core temperature, and put you in danger. But performance fabrics are designed to prevent that from happening by keeping the wearer warmer in cool temperatures, and cooler in warm ones. How exactly does that work? Many of the high tech fabrics used in performance gear today have the ability to sense when they have gotten wet, and react accordingly. Tiny membranes in those fabrics will often open up when touched by moisture, allowing more air to pass through. This in turn helps them to dry quicker and allows the body to cool down more efficiently as well. As the moisture evaporates, those same membranes will begin to contract, helping to prevent too much air from leaking in. The more they close, the warmer the garment becomes as a result.
Unfortunately the outdoor industry hasn’t developed any type of standard for measuring breathability in a product so it is often difficult to compare one piece of gear to another. It is challenging enough to differentiate products that fall into the same category, but it is next to impossible when those pieces of gear are meant to do vastly different things. For example, a running shirt performs much better in terms of breathability than say a rain jacket, but both can be described as being “breathable” provided the fabrics that make up the two garments offer some level of venting and moisture control.
As a rule, any piece of gear that provides a measure of waterproofing will breathe much less efficiently than one that does not. Waterproof fabrics that can breathe must possess the ability to allow moisture to escape, while also preventing it from getting back in. That can be a very challenging thing to achieve, although there are several fabrics on the market that can do this – including Gore-Tex, Columbia’s OminiDry, and Mountain Hardwear’s Dry-Q. But the performance of these fabrics is measured in relative terms, which means we must set our expectations accordingly when measuring how well they succeed at breathing.
For outdoor enthusiasts the increased focus on breathability in our gear is important because it keeps us far more comfortable – not to mention safe – while out doing the things we love. Breathability means we stay cooler when we get warm, and we stay warmer when the temperatures gets cooler. It also means we stay much drier in all conditions as well, which is something that I think everyone can appreciate.