The advantages of nasal breathing during cardiovascular exercise.
If you want a more in depth explanation of why nasal breathing during exercise is superior, check the book "The Oxygen Advantage." This is just a brief summary of the ideas. The breath is a powerful thing and the cardiovascular system is really intricate and it's a complicated subject that requires a lot of looking into to get the full picture. The cardiovascular system is the working infrastructure for everything in your body. This is just one small part of the picture.
If you live in a colder climate, you have definitely experienced the cough that you get after you go on long run. This is what happens when you inhale cold, dry air straight into your lungs. You can avoid this through breathing through the nose as it acts to filter and warm the air as it enters into you. On top of this though, there's lots of athletic/health benefits to breathing strictly through the nose while training.
