what you breath and how you breath fuels you. Breathing and training in ways to improve your O2 uptake can help tremendously with physical performance and endurance. Firstly, practicing slow, deep belly breathing through the nose should be the primary way of breathing as a day to day habit. Most people are habitual mouth breathers which is not good as a lifestyle habit, creating more anxiety and poor O2 uptake. It is actually Co2 which contributes to O2 absorbtion in the blood, so practicing breath holds through the Bolt method can be highly useful for atheletes and increasing physical performance.