Ace of base: How ZeroFit make the 'world's warmest base layer'

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You have to have the utmost confidence in your garments to trademark them as the ‘world’s warmest base layer’ but that’s just what ZeroFit have done.

The ‘Heat Rub’ technology was developed by Japanese rider Koji Higashi as a way to continue his favourite outdoor activities when the winter weather arrived.

The base layers, which include long sleeved tops, leggings, snoods and socks, not only trap the body’s heat, but also actually produce heat as you move around.

Friction holds the key Firstly, an outer layer constructed from hollow polyester insulates the rider from the cold.

Beneath this is a 45% polypropylene thermoplastic construction that aids in regulating body temperature by removing sweat from the skin through the hollow polyester shell, ensuring it evaporates off the surface of the garment quickly. This is so the unpleasant experience of cold sweat can be avoided.

It’s beneath the outer layer where the hot science happens as long, micro-filaments called ‘Heat Threads’ actually generate warmth via friction as they gently brush against the skin. It is the textile equivalent of rubbing your hands together on a cold day.

Testing by leading textile evaluation facility, the Boken Institute in Osaka, has rated the garments’ CLO score as 0.78. The CLO is the system is used to measure the warmth levels of various materials.

It’s determined based on the insulation levels needed to keep a person at a comfortable level while standing in a room at a controlled temperature and humidity.

A completely unclothed person has a base rating of zero. To put the score into real world applications, a sweater has an average CLO of 0.3 while a winter coat can measure 0.70.

Additionally, and of interest to motorcycle riders, is that ZeroFit does not rely upon compression to increase body temperature.

Compression increases blood flow to the restricted areas, raising heat, but the downside is base layers that rely on this method can be restrictive on a long ride.

ZeroFit clothing still requires a snug fit, but the outer material is woven in such a way as to allow movement in all directions without restriction.

ZeroFit base layer worn under leather suit

The kit is available in two levels of protection – the Ultimate for temperatures between -10°C to +10°C, and the Move which is for slightly milder climates.

Michael Morton, MD Zerofit Europe said: “While we have a number of projects ongoing that we can’t speak about just yet, one area I can tell you we are looking at is producing Heatrub Ultimate Gloves – this was something that came from consumers.”

For more information visit the Zerofit website.