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I heard a clinician speaking about the importance of matching clients with the right wheelchair cushions, so that their skin can breathe, to which I wanted to ask, “Exactly what type of amphibians are you seating – frogs?”

Of course, we, humans, don't breathe through our skin – the clinician merely made a common mistake, choosing the wrong words for the real issue, heat build-up and perspiration from sitting. See, when we place a surface like a seat cushion against our body, it traps our body heat, we perspire in that region, then that moisture can cause skin breakdown – as in, pressure sores – if not promptly removed. Therefore, as those sitting on wheelchair cushions, our goal is to minimize heat from the seated region of our bodies, and promptly wick away any perspiration that occurs. Fortunately, both of these goals are facilitated with the right pressure-management cushion and cover materials.

Heat: From the Inside, Out
If you think about a seat cushion as an insulating layer against the seated region of your body, it becomes obvious that the cushion's material, itself, plays a role in regulating heat.

Gel
Gel proves as among the “coolest” seating surfaces because it doesn't retain heat as well as other materials. In fact, if you've ever touched any sort of “gel” material, then you've experienced how it's usually cool to the touch. In this way, while a gel pack still traps body heat by nature of its sealed pack being against the body, its intrinsic heat-dissipating properties keeps the gel cooler, thereby keeping the seated area cooler, which helps minimize perspiration.

Foam
Traditional foam seating surfaces are insulating to varying degrees, based on the type of foam, so they do trap body heat to an extent. However, some newer cushion technologies use “engineered foams” that are extremely porous, like a honeycomb or filter, allowing air to circulate within them, dramatically dissipating body heat, to the tune of 3-degrees cooler than other cushions.

Air
Despite their name, air cushions prove among the least effective at dissipating body heat, where very little air circulation or “cooling” occurs. While some manufacturers claim that air can circulate in-between the cells of an air cushion, the fact is, when you're seated on the cushion, it spreads the cells into each other, creating an almost constant barrier against your body. Furthermore, most air cushions are made out of neoprene – a material that's a literal insulator – trapping body heat. For these reasons, air cushions are often the least effective at dissipating body heat.

Now, this isn't to say that of the three materials – gel, foam, and air – any one is least effective at overall pressure management than the others. Truly, they all prove exceptionally meaningful at pressure relief for specific individuals. However, if heat build-up is an especial concern for you, then the properties of cushion materials in this aspect most certainly come into play.

When What's on the Surface Matters
Make no mistake, a cushion's cover plays a foremost role in moisture control – and can even prove more consequential than a cushion's material, itself, toward regulating heat build-up.

Sheepskin was once thought by many as among the best materials to decrease heat and moisture build-up. And, while that was true compared to circa 1970s vinyl (which had no moisture-wicking properties), modern seating covers prove sheepskin as among the worst materials to sit on. Sheepskin is an insulator – wool – that is among nature's finest material at trapping body heat, so while sheepskin wicks away moisture, it dramatically increases perspiration, the antithesis of a healthy-inducing cushion cover. Therefore, in modern wheelchair seating, sheepskin covers are avoided.

Contrary to the sheepskin and vinyl cushion covers of the past, today's covers are engineered for four purposes:

1.Reduce heat build-up by not insulating the body
2.Wick moisture away from perspiring regions
3.Stretch to optimize conforming to pressure relief surface
4.Provide a low-shear surface to reduce skin tension

The result is that most pressure-management cushions today use variations of moisture-wicking Lycra materials that are strikingly along the lines of an athletic clothing brand that you might know, Under Armour. In fact, Under Armour describes their material as “wicking moisture away from your skin, and helping regulate your body's temperature” – and that's exactly what modern moisture-wicking cushion covers accomplish.

Because today's pressure-management cushions covers perform so well at reducing heat build-up and wicking away moisture, it's inadvisable to use any cover material beyond that which was engineered with the cushion.

No, modern pressure-management cushions and covers may not look as plush as sheepskin, but they're that way by design – that is, to keep your seated regions cooler.

Published 4/2010, Copyright 2010, WheelchairJunkie.com