How Training Makes Us More Efficient

As we get fitter, our production of heat at a given intensity goes down because our capacity is up. But then what's happening on the other side of that particular equation is that your heat loss capacity goes up as fit people have got better capacity to lose heat through sweat. Their blood flow redistribution works more effectively so they can bring that hot blood to the surface of the skin and then lose it to the environment. And they can also sweat, as I said, to their sweat more.