A fever is, at it’s core, an increase in metabolic rate. Your hypothalamus is telling your body that it’s temperature set point is higher than usual, and it tak

A fever is, at it’s core, an increase in metabolic rate. Your hypothalamus is telling your body that it’s temperature set point is higher than usual, and it takes energy to raise your temperature. I don’t see how a difference in air pressure would have a similar effect.