Overbreathing which occurs as part of the fight or flight response – an alarm reaction allocating the body’s resources to protect you from danger – brings about a short-lived imbalance between oxygen and carbon dioxide in the blood. Once fight or flight begins, oxygen is consumed and carbon dioxide is produced, restoring balance to the blood.
If you do not flee or flight, the imbalance between oxygen and carbon dioxide remains for longer periods. The build up of oxygen in blood is not a cause for concern. However, the drop in carbon dioxide causes problems. Although there is plenty of oxygen in blood, they are not released from the red blood cells. Breathing out your carbon dioxide has made the red blood cells become sticky for oxygen. Paradoxically, by breathing in more oxygen (and breathing out more carbon dioxide) you reduce the oxygen reaching the body’s cells.
In addition, overbreathing has another important effect. It can causes the blood vessels to shrink. Consequently, the oxygen being released has to travel further from the blood to the cells. As a result, little oxygen reaches the cells of the body adn brain.
These two effects – the decreased released of oxygen from the red blood cells and the shrinkage of blood vessels to produce a variety of sensation which, to the anxious person, sound all to familiar. As less oxygen reaches the body and brain, they begin to work less efficiently. This slight and harmless drop in oxygen will be experienced in the following ways:
- Blurry vision
- Feelings of unreality
Breathlessness is the brain’s recognition that something is not quite right. As a result, you will breathe more heavily and deeply. However, this strategy will make the situation worse, because you will breathe out even more carbon dioxide.
There is also decrease in the amount of oxygen reaching the body’s cells. The person experiences a variety of sensations associated with the decrease in oxygen. Common sensations include:
- Increased heart rate (to pump more blood around the body).
- Numbness and tingling in hands and feet.
- Clammy hands.
- Stiffness and shakiness in the muscles.
- “jelly legs”.
As well as the direct effects of overbreathing, there are number of indirect effects. Since overbreathing is hard physical work, the person may feel hot, flushed and sweaty; not to mention tired and exhausted. Overbreathing also involves quick, short breaths taken from the chest. The muscles become tired, leading to chest pain and tightness. And overbreathing causes saliva to evaporate, leaving the mouth dry.
If overbreathing persists, the body changes strategy. Until now it has been encouraging you to breathe faster and harder. Now it attempts to slow your breathing down to increase the level of carbon dioxide in the blood. For example, your throat will tighten to reduce the amount of carbon dioxide breathed out and to reduce the amount of oxygen breathed in. If successful, the build up if carbon dioxide will allow the available oxygen to be released from the red blood cells. During this second stage of overbreathing, the person will experience the body’s effort as:
- Dizziness or nausea.
- Choking or smothering (as the throat closes slightly).
- Temporary paralysis of some muscles.
- Momentary blackouts.
In a nutshell, overbreathing is not physically or mentally dangerous. It is a normal part of the flight or fight response. Overbreathing causes an imbalance between oxygen and carbon dioxide which decreases the oxygen reachinf the body and brain. This in turn produces bodily and mental sensations which contribute to a rapid increase in anxiety.