1. THERE IS AN IMPORTANT RELATIONSHIP BETWEEN OXYGEN AND CARBON DIOXIDE (THE BOHR EFFECT).
For normal, healthy functioning, your body needs a certain amount of oxygen to survive. And it needs carbon dioxide too. Despite what you may remember from school science lessons, CO2 is not just a waste gas. In breathing chemistry, it works hand in hand with oxygen.
During inhalation, air enters the lungs and travels to the alveoli. There, oxygen diffuses to the blood. It’s picked up and carried through the blood vessels by the hemoglobin molecules in red blood cells. This oxygen-rich blood is pumped throughout the body by the heart, and oxygen is offloaded to the cells for conversion into energy.
In order to release oxygen from the blood, hemoglobin requires a catalyst. This is where carbon dioxide comes in. CO2 is responsible for the release of oxygen from the cells to the body. It acts like a hormone in the blood, enabling the release of oxygen in the same way that insulin prompts the release of blood glucose.
This function of carbon dioxide was discovered in 1904 by physiologist and Nobel laureate, Christian Bohr. Bohr reported that as the pressure of carbon dioxide increases in the blood, blood pH drops (making the blood more acidic), and oxygen is released more readily. When carbon dioxide levels are low, hemoglobin is less able to release oxygen from the blood. This means the way you breathe determines the concentration of carbon dioxide present in your blood, and how well oxygenated your body is.
During physical exercise, working muscles use more oxygen, so the body needs more oxygen to give you energy. At the same time, your body temperature rises, and your cells produce more CO2. The extra CO2 releases more oxygen from the red blood cells, which is then available to the cells and organs. John West, author of Respiratory Physiology, explains: “An exercising muscle is hot and generates carbon dioxide, and it benefits from increased unloading of O2 from its capillaries.” The better you can fuel your muscles with oxygen during activity, the longer and harder they (and you) can work.
When you hyperventilate (breathing in excess of metabolic requirements) you exhale too much carbon dioxide from the lungs. This causes the concentration of CO2 in the blood and cells to reduce. When carbon dioxide levels are low, the transfer of oxygen from the blood to muscles and organs is inhibited, leading to poor body oxygenation. This poor body oxygenation is one reason you feel breathless and “gas out” during exercise.
Breathing too much air reduces blood flow to tissues and organs including the heart and brain. This is why Wim Hof cautions that you may feel light-headed during his breathing exercise. In fact, blood flow to the brain reduces proportionately to the drop in carbon dioxide (Magarian et al., 1983). A study published in the American Journal of Psychiatry, which assessed arterial constriction induced by excessive breathing, found that the diameter of blood vessels reduced in some individuals by as much as 50 percent (Gibbs et al., 1992). Based on the formula [pi] r squared ( A = πr2), blood flow will decrease by a factor of four. This shows you how over-breathing can affect your blood flow.
The Bohr Effect confirms that Wim Hof’s practice of taking 30 large mouth-breaths will lower the concentration of carbon dioxide in the blood and limit the release of oxygen from the blood to the cells. CO2 plays a central role in regulating the acidity or alkalinity (pH) of the blood. Hof uses this mechanism to trigger temporary alkalosis (an increase in blood pH).
2. BLOOD PH IS REGULATED BY THE BREATH.
Normal blood pH is 7.365. The pH of the blood affects your metabolism and the function of your internal organs. If blood pH is too acidic and drops below 6.8, or too alkaline and rises above 7.8, the result can be fatal (Casiday et al., 2014).
Respiratory alkalosis can prompt changes in the nervous system and in physical and psychological states. It causes symptoms including breathlessness, chest pain, headaches, fatigue, dizziness and light sensitivity. It can even lead to the development of myofascial trigger points (Bradley & Esformes, 2014). Over time it has a significant negative effect on the musculoskeletal system and is detrimental for health and performance.
The Wim Hof breathing method induces controlled respiratory alkalosis. The empty lung apnea (breath hold) that follows the 30 big breaths then normalizes the relationship between oxygen and CO2by causing a marked decrease in SAO2.
The Oxygen Advantage® uses CO2differently. Patrick’s method focuses on reducing the body’s sensitivity to CO2, regulating breathing biochemistry for more efficient breathing, delayed onset of breathlessness and fatigue, and better oxygenation day and night. The exercises tosimulate high altitude trainingincrease the oxygen carrying capacity of the blood by prompting the production and maturation of new red blood cells.
3. WHY BREATH HOLDING AFTER EXHALATION IS GOOD FOR YOU.
When you hold your breath after a normal exhalation, CO2builds up in the blood and oxygen floods to the cells and tissues. The diaphragm begins to contract, as the brain signals to the body to begin breathing again. This gives your breathing muscles a strong workout.
If you practice the same breath hold after deliberate hyperventilation, you will be able to hold your breath for longer periods of time, because levels of CO2are not high enough to trigger the brain’s respiratory drive. Again, as you reach the end of your breath hold, you will experience strong movements of your diaphragm as your body tries to take in air.
Wim Hof explains that taking big, deep breaths prior to the breath hold, “fully charges the body by getting rid of carbon dioxide, allowing more oxygen into the body to roam freely and fill up every cell, and increase pH levels.”
This differs from the Oxygen Advantage®strong breath holds. In the Oxygen Advantage®method, one of the effects of breath holding is that it causes the spleen to contract and release new red blood cells into circulation. It also boosts natural production of EPO, which stimulates release and maturation of new red blood cells. These two factors actually increase the oxygen carrying capacity of the blood. Since the blood is already saturated with oxygen (about 98% of oxygen is carried around the body in hemoglobin and 2% is dissolved directly in the blood) this is the only physiological way to increase blood oxygen saturation.
4. WHAT HAPPENS WHEN YOU BREATHE “HARD”?
Breathing “hard” activates your diaphragm. It also affects oxygen delivery to your tissues, working muscles and organs including the brain. Chronic hyperventilation (habitually breathing too much air) is at the root of a huge range of health symptoms including panic attacks, insomnia and even PMS.
Hard breathing changes the body chemistry. It’s what Hof is trying to achieve in order that the body makes certain beneficial adaptations. And it’s what Patrick McKeown is trying to help us avoid in our everyday breathing.
During rest, the normal breathing volume for a healthy person is between four and six liters of air per minute. This results in almost complete blood oxygen saturation (95-99%). Oxygen is continually diffusing from the blood into the cells and tissues. Complete oxygen saturation (100%) would indicate that the blood cells are not delivering oxygen to the body. The oxygen-carrying red blood cells must release oxygen, not hold onto it.
The human body actually carries a surplus of oxygen in the blood. During rest, 75% of inhaled oxygen is exhaled. Even during physical exercise, when the working muscles and breathing muscles need a much greater supply of oxygen, as much as 25% of inhaled oxygen is exhaled.
Once we become interested in the breath, our goal is often to “get more oxygen.” But the best way to do this is to develop more efficient breathing to optimize body oxygenation. The idea that you need to increase blood oxygen to 100 percent saturation is a misunderstanding of breathing chemistry.
