The average human being has a resting heart rate of approximately 70 beats per minute. Miguel Indurain has one of the most legendary heart rates of all time, with a reported 28 bpm, with most endurance athletes clocking in around 40bpm. When Phelps pulled his swim goggles off and relaxed on dryland, his resting heart rate was a steady 38bpm, meaning that his heart was more efficient at pumping blood to his muscles than his competitors.