With the Australian Open hitting the headlines for heat rather than tennis, we ask UCL’s Professor Hugh Montgomery about what happens to your body when you play tennis in 40 plus degrees?
“Maintaining a steady core body temperature is essential to human health and survival. When external environmental air temperatures exceed those of the human body, heat is delivered to that body by convection. Solar radiation adds to that heat gain- and the body becomes a net 'absorber' rather than 'emitter'. Exercise adds additional heat gain: about 75% of the 'work' of exercise comes out as heat. The only way that this total heat burden can be removed is through evaporation of sweat (which can amount to some 2-4 litres/hour). Even this may be insufficient if the air is humid and dehydration can critically impair this ability. It is for these reasons that exercise in extreme heat poses such a hazard- especially to those acclimatised to such conditions (exposure increases sweat rates over time.) The increasing frequency and severity of extreme weather events is likely to make these threats increasingly problematic “