So there's this free sample thing in the magazine and an associated RW Promotion feature on pages 82 & 83 of the new issue of Runner's World.
Some Breath Thermo yarn from Mizuno - add a few drops of water (provided!) and the yarn gets hot.
It really does!
And the application of this... making apparel that, when you start sweating, HEATS UP!
"Breath Thermo technology reacts with perspiration to generate heat..."
"Drawing on Mizuno's 100 years of sports technology expertise, the Breath Thermo fabric works by taking advantage of the moisture produced when you perspire. It .... then uses the water vapour to activate heat-generating fibres in the fabric."
Now hang on... why do we sweat in the first place?
It's the body's way of trying to cool itself when it overheats - so why do we then want to be made to get even hotter?