You might well sprint 20 yards or lift 50 pounds without inhaling even once. Distance running, however, requires breathing to energize the muscles. Runners also have a pronounced need to exhale carbon dioxide, or CO2 -- a potentially dangerous byproduct of oxygen use. To improve endurance, elevate your maximal oxygen consumption through regular exercise. Raise oxygen intake while expelling more CO2 by controlling the rhythm of your breathing.
Distance runners have a heightened need for oxygen. The muscle fibers primarily involved in distance running acquire energy through a metabolic process that requires oxygen and generates the waste product CO2. To obtain vital oxygen, expel potentially dangerous CO2 and develop endurance, respiration must increase when you go from rest to high-intensity distance running.
When drawn in through mouth, nose and air passages, inhaled oxygen eventually reaches tiny air sacs deep inside your lungs. Little blood vessels embracing these air sacs expose blood to inhaled oxygen. Oxygen is picked up by your red blood cells, then carried in the bloodstream to your leg muscles and elsewhere.
In normal breathing, you exhale large quantities of potential acid in the form of CO2 gas. While running, you must breathe harder to expel this potential acid, as your muscles consume more energy and oxygen, producing more CO2. The inadequate elimination of CO2 due to asthma, bronchitis or emphysema, for instance, would not only diminish a runner’s endurance, but could lead to an irregular heartbeat, a weakened heart muscle, low blood pressure, tremors, seizures or lethargy.
Breathing's effect on endurance is not fixed. Habitually performing endurance exercises can increase your capacity to consume oxygen. This means that, as your skeletal muscles and cardiovascular system adapt to regular distance running, you can attain higher levels of endurance at the same respiration rate. For most people, jogging 20 to 30 minutes three times weekly can raise maximal oxygen consumption, according to the text, "Human Physiology: The Mechanisms of Body Function."
The respiratory center in your brainstem normally adjusts respiration rate to handle changing oxygen needs while expelling CO2 without your awareness, according to the book “Principles of Human Anatomy.” You might, however, benefit from consciously altering the rhythm of your breathing to enhance endurance, suggests fitness expert Stew Smith. To increase oxygen intake while expelling more CO2, adopt a 3-to-2 inhale-exhale ratio, meaning that distance runners should inhale on the left-right-left foot strikes and exhale fully on the right-left foot strikes, notes Smith.
- Biology, 5th Ed.; Neil A. Campbell, Jane B. Reece and Lawrence G. Mitchell
- Human Physiology: The Mechanisms of Body Function, 8th ed.; Arthur Vander, James Sherman and Dorothy Luciano
- Medical-Surgical Nursing, 6th Ed.; Joyce M. Black, Jane Hokanson Hawks and Annabelle M. Keene
- Principles of Human Anatomy, 9th Ed.; Gerard J. Tortora
- Military.com: Breathing During Exercise; Stew Smith
- Photo Credit Comstock/Comstock/Getty Images