Cardiorespiratory fitness is heavily dependent on the availability of creatine to the working muscles.

While creatine can enhance muscular performance and may contribute to an increase in cardiorespiratory fitness indirectly, it is not the sole or primary determining factor for cardiorespiratory fitness. Factors such as lung capacity, heart function, and the ability of the body to efficiently transport and utilize oxygen also play important roles in determining cardiorespiratory fitness.