Research shows that there are differences in breathing capabilities between men and women (PubMed). The rate of breathing is mostly determined by the heart and the lungs. The lungs are responsible for taking in oxygen, which is then bound to the red blood cells and pumped by the heart to the rest of the body through an intricate network of capillaries, veins, and arteries. The reverse occurs when carbon dioxide is expelled from the body. Men are capable of achieving a higher heart rate than women. This affects the amount of oxygen the lungs and heart can deliver to the body. In addition, men have a larger heart and lung capacity compared to women. Under strain, for instance, during physical exercises, the breathing capacity in women is limited compared to that of men. Thus, the input and output with regards to breathing are different between the sexes largely due to structural and functional distinctions.