Explain the energy transformation that occurs when a person exercises

According to the First Law of Thermodynamics, energy is neither created nor destroyed. It is only being transferred from one form to another.

Everything that we do requires energy. Thus, following the first law stated above, we can say that there is an energy transformation when we exercise. These transformations are described as follow:

1. The food that you eat contains various forms of chemicals that are being stored in your body in the form of chemical energy.  When the food you eat is combined with oxygen, a chemical reaction takes place. During the process, chemical reaction bonds hold the atoms together are broken down to release energy. 

2. When the energy begins to put you into work, the chemical energy is now a potential energy is being transformed into kinetic energy.

3. Say the exercise involves riding a bike, the kinetic energy is now being transferred into the pedal in the form of mechanical energy.

4. Constant rubbing of the feet to the pedal may also transform some of the energy into heat, thus forming thermal energy. Likewise, your body may heat up during the exercise, that will also lead to thermal energy transformation.