Men’s hearts are 20-25% larger than women’s, particularly in the left ventricle.
This increases the ability to pump oxygenated blood around the body to be used in the muscles, making it easier for males to run faster for longer.
The primary male hormone is testosterone, which stimulates muscle mass development. The female primary hormone is estrogen, which stimulates fat accumulation.
Testosterone also increases the concentration of red blood cells, and hemoglobin, both critical for transporting oxygen around the body.
This means that on average male blood can carry around 11% more oxygen than female blood to increase efficiency to run faster.