A nerve fires on a sodium gradient. Drinking only water during long effort can wash that gradient down.
The first response to cold is sympathetic. Thyroid hormone turnover changes on a slower clock than shivering.
Working muscle ships lactate as a fuel other tissues can oxidize. The burn is not lactate acting as a toxin.
After orgasm, prolactin often rises and oxytocin can rise with it. The next hour is a hormone shift, not a cure.
