Those who exercise, especially athletes, often have larger than average lung capacities as a result of taking deeper breaths more often. Why? Because deep, rhythmic breathing expands the diaphragm muscle and the air pockets within the lungs. This allows for more oxygenation of the cells within the body which improves health, helps all the body’s systems perform better, and even can provide you with more energy. Deep breathing actually helps to stretch out the torso, you needn’t look any further than at the Olympic swimmers who typically have very large torsos to see this in action. Humans need oxygen for complete cell development. It’s impossible to be healthy if you’re not getting enough oxygen.