We evolved in a certain context over billions of years. And part of that context is related to temperature fluctuations. How we operate in the cold winter is a bit different than in the hot summer.
When we’re faced with a stressor, such as an infection, an injury, new information, or toxic chemicals, our body often uses strategies and physiology that’s based on normal day to day physiology and just turns things up a notch. For example, when we’re infected with a virus, our body uses Summer physiology and cranks it up so that we sweat and have a fever.
Part of the benefit of increasing our temperature is to increase the levels of something called heat shock proteins. We produce more of these when we’re hot or have a fever and these help us do a much better job of accurately folding our proteins, which is extremely important for overall health.