Question: Why does our body temperature raise while doing sport? Is it due to the speed of metabolic reactions in our cells going quicker and quicker so our our muscles can have the amounts of oxygen that they need to do exercise or something like that?

Dan Gordon answered on 7 Nov 2016:

Hello Smart girl. Well your explanation is rather good and not far from the truth. If you think about a muscle contracting, to do this energy is needed, this comes in the form of a molecule abbreviated as ATP. When this molecule is split (using water) energy is released, and it is this energy that allows for the muscle to contract. However, you should remember that energy = heat and 75% of this energy from the splitting of ATP is lost in the form of heat. SO this heat has to go somewhere, removed fro the body. If the muscle is contracting slowly this would imply that there is not a great demand on metabolism which is the process of using substrates such as carbohydrates to produce the ATP before it is split. However if the demand at the muscle goes up (could be running faster) then metabolism increases to meet this demand and of course more ATP is split meaning we generate more heat. This is referred to as the Q10 effect. Additionally there is a point when the oxygen that we consume (which is used to fuel metabolism) can not meet the demand and so metabolism speeds up even more, (starts to work anaerobically). this now produces ATP approximately 18 times faster than when O2 was available, which means that the heat produced also increases significantly.