The cells in your body need oxygen in order to create energy. This energy is in turn used to power the body. You muscles, organs, brain etc. We get the oxygen from the air we breath into our lungs. The same cellular process, called cellular respiration, that burns oxygen to create energy creates carbon dioxide as a waste product. The waste carbon dioxide moves into the blood stream and then into the lungs.
Inhale , pulls air rich in oxygen into the lungs for the body to use. Exhale , pushes air heavy with carbon dioxide out of the lungs and clears space for clean air to come in on the next inhale.
The amount of Carbon Dioxide in the air around us is 0.04 %. Meanwhile the normal amount of Carbon Dioxide present in our lungs due to cellular respiration is between 4 and 5%. Obviously the harder you exercise the faster you need Oxygen delivered to the cells and the more Carbon Dioxide your body will produce. It is not a lack of Oxygen in your cells that triggers the breathing reflex but rather the excess of Carbon Dioxide in your blood. In fact if you run out of Oxygen you will pass out because your brain would not be able to function.
The total amount of air you can breathe in a minute is determined by the size of your lungs and the number of breaths you take per minute. When you are running you should look to get into a breathing rhythm. A breathing rhythm is number of steps per inhale, followed by a number of steps per exhale. In a 3-3 rhythm you inhale for 3 steps and exhale for 3 steps. Most experienced runners get into a 2- 2 rhythm when they are racing or running fairly hard. 3 – 3 is a more relaxed and easier run. It’s worth experimenting with different breathing rhythms including. 3- 3, 3-2, 2-2, 2-1, 1-1.
For our purposes of distance running 2 – 2 is best. Let me explain why. Assume that your lung capacity is 2 liters per lung so each time you fill your lungs that’s 4 liters of air. Assume also that you have a constant stride rate of 160 steps per minute. If you are running at a 4- 4 rhythm then that is 8 steps per breath cycle and so 20 breaths per minute. 20 x 4 liters – a total of 80 liters of air is processed per minute. Lets look at 3 – 3 or a total of 6 steps per cycle and 160 steps per minute gives us 26 breaths but at this rate we will only be able to get about 3.5 liters in before the exhale. Giving us 26 x 3.5 = 91 liters. At 2 – 2 you get 40 breaths per minute and about 3 liters on each cycle. Giving us 120 liters per minute. If you go on to a 1- 1 rhythm you will greatly reduce the amount of air you can take in on each breath and the amount of air per minute will probably be less even than at 4 -4.
So from that you can see that a 2 – 2 rhythm gets the most amount of air and therefore oxygen into our lungs in a minute. 2 -2 is best for distance running but the last portion of a race will probably work best at 2 -1.
In part 2 we will look at the Mindful aspects of breathing