Respiration is an exothermic process because it releases large amounts of energy to the surroundings.
During respiration, glucose molecules are converted to other molecules in a series of steps. They finally end up as carbon dioxide and water.
The overall reaction is------------>
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 2805 kJ