DR ANDREW SELLARS

“The main reason you breathe faster with higher intensity exercise is to blow off CO2, which is a byproduct of metabolism. So the harder you work, the more CO2 you produce, the harder you have to breathe to blow it off.”

“If you rebreathe some CO2, you can balance your physiology. And now you can actually train your breathing for as long and hard as you want without actually negatively affecting your physiology and without having to drive the body to levels that would be really hard to mimic a race without riding really really hard.”

“That brilliant book, but it really should have been called the CO2 advantage, the carbon dioxide advantage, because all of the the entire book is about this understanding of what happens to your body with higher levels of CO2 and the physiologic benefits of higher levels of CO2 if you can tolerate it.”