10 minutes at 2.8°C today – near 2000m altitude close to the Cormet d’Areche – close to home. It would be a good stream for whisky making as there is a lot of vegetation in the sediment with the water being brownish instead of the usual sparkling clean glacial clay at this altitude. (Either that or it’s cow poop) Not managing to get into the cold very frequently just now but the adaption seems to be improving all the same. Even after 10 minutes in cold running water it only took minutes to warm up again – without shivering. That’s what’s meant by “cold thermogenesis” – it’s all about generating heat from brown fat and not from mechanical actions. There’s two ways to build brown fat – cold exposure and endurance exercise. Brown fat burns white fat – so being ketogenic probably helps. The nervous system also adapts so that there is a major reduction in pain sensitivity – at least in the skin. It’s supposed to create an epigenetic effect – rewiring the hypothalamus – which is where control over body temperature resides. 