When a person is doing some exercise,the energy is produced from breaking the bonds present in the stored molecules and compounds.This leads to availability of the energy in the body to perform the work. Now, the body wants to maintain the optimum level of temperature inside the body, which then leads to releasing of extra energy to stabilize the body. The sweating glands are opened for releasing water molecules and we feel more thirsty.Along with that urine is also released to stabilize the system.
