The ideal skin temperature is 32˚C, however, when sitting against a normal backrest the skin temperature rises 2.2˚C on average within 30 minutes. Tests show that the temperature of a backrest can increase from 23˚C to 34˚C in 100 minutes, creating lots of unwanted heat and moisture. This moisture can lead to skin maceration.

WheelAir helps control temperature, sweat, and microclimate. Our tests show that the WheelAir Cushion Cover can lower temperature by 6°C and reduce relative humidity by 41%, and the WheelAir Slingback can prevent an increase in temperature of 9°C and reduce relative humidity by 25%.

Read our Temperature & Humidity Tests

Microclimate & moisture lesions

Moisture lesions or moisture-associated skin damage (MASD) is defined as inflammation and erosion of the skin caused by prolonged exposure to moisture. Unlike a pressure sore, MASD occurs on non-bony parts of the body too. Moisture lesions cause superficial loss of epidermis (the top layer of the skin) and/or dermis (the second layer of skin), which may be preceded by areas of erythema on intact skin.

The effect of moisture on the skin can be damaging, especially trapped moisture which is often a result of poor air circulation. Excessive moisture will affect the dermis by weakening the collagen and softening the stratum corneum in the epidermis which can lead to maceration. Macerated skin can be recognised as pink or white surrounding skin with non-uniformly distributed redness at the centre.

How and when does excessive moisture occur?

An increase in the metabolic rate increases the body tissues’ susceptibility to the ischaemic effects of shear and pressure. Sweat is then produced to regulate the body’s temperature. Equally, where the body and support surface come into contact, a rise in temperature may occur due to increased pressure, causing occlusion of the circulation, inflammation and an accumulation of warmth between the skin and the surface. As heat builds up, moisture will accumulate causing the skin to feel damp.

Previously, the only method to help evaporation of moisture and aid in cooling affected areas was to reposition the person or advise the person to reposition themselves. Now, the WheelAir technology will now do this automatically, without any necessary repositioning.

Microclimate & pressure ulcers

Pressure is just one key factor in pressure ulcer development. The microclimate is controlled at the seat surface, which should be considered when choosing the appropriate surface for you. It is important that the backrest is moisture and air permeable so that it will not lock in moisture which can soften and macerate the skin, making it more vulnerable to pressure and friction.


Areas prone to skin ulcers which WheelAir predominantly covers are the spine, sacrum and coccyx. When choosing a hard-shell back, attention should also be paid to the shoulder blades. Clinical evidence shows that elevated skin temperature leads to a higher incidence for tissue damage. Similarly, due to the moisture, the macerated skin in contact with a solid surface equals a higher coefficient of friction. Friction leads to skin shear, which leads to tissue ischemia and localised tissue necrosis.