If you don’t think that your lungs are a muscle, run as fast as you can for three minutes and reconsider. The lungs have a simple yet important function: the delivery of oxygen through the body. The simple act of breathing can expand your ribs, bringing more oxygen into your blood stream. This will help you exercise longer without feeling winded and will make you feel a rush of energy. 1. Sit upright, expel all the air from your lungs. 2. Slowly breathe in, expanding your lungs to maximum capacity. 3. Hold the air for as long as 20 seconds. 4. Expel the air slowly and relax.