Shortness of breath is a particularly difficult feeling to live in immersion. If it is not controlled and mastered, it can lead to dangerous behavior for the diver. The objective of this article is to present the main reasons of the breathless sensation while diving and how to manage it. The Hyperventilation is one of the main scuba diving risks .
As everyone knows our body imperatively needs new air in order to function. It can be compared to a large, somewhat special chemical plant. Our cells need oxygen to work, just as machines need electricity to work. Outside, this work produces waste that must be evacuated. This waste is partly carbon dioxide. Oxygen and carbon dioxide are carried by the blood that transports between the lungs and the whole body. It is in the pulmonary alveoli that the exchange between oxygen and carbon dioxide is done by osmosis, a phenomenon of gas transfer through the thin wall of the cells. In short, we must absorb oxygen at the inhalation and release carbon dioxide at expiration.
It seems important, before going into too much detail, to remember some basic notions of breathing or rather our breathing abilities.
Breathing, in common sense, is the alternation of fresh air entering our two lungs and the expulsion of stale air charged with CO2, thanks to a few muscles, the main one being the diaphragm. To give an idea, we carry out an average of 22,000 to 23,000 respiratory cycles per day, which represent 16 to 22 breathing cycle per minute. The respiratory cycle varies from one person to another and depends on several factors such as age, health, fatigue, stress level or reaction to violent efforts. Our lungs are not quite identical, the heart occupies in the thorax a non-negligible place that decreases the volume available for the left lung. For simplicity, we admit that on average we have a respiratory capacity of about 4.5 to 5 liters of air.
When we breathe in, only 0.5 liters of air is renewed. This may seem rather small compared to 4.5 liters, but it is very sufficient in normal living conditions. It is easy to imagine that the large part of the non-renewed air ends up being saturated with stale air and therefore containing a lot more carbon dioxide than in the surrounding air (up to 5 to 6%). Nothing annoying at normal atmospheric pressure, but we will see it, it is not the same in depth. To get rid of this carbon dioxide stored in the lungs, it is necessary to voluntarily perform a forced and deep expiration. This allows you to renew up to 2.5 liters of additional air.
While writing these lines, I can’t help thinking of my first breathing problem while diving. I just started my Open Water Course in Thailand and we had to descend in the blue for my first open water dive, to arrive at 18 meters. During the descent, I felt a little bit stress and few meters to to arrive to the sandy bottom, I had felt a strange sensation. My heart was pounding and I felt that the regulator was not delivering enough air, a horrible feeling of lacking air made me start to panic. The other started to move on and palm. I should have reacted earlier, I had waited too long to signal my embarrassment and I was already at the tail of a divers and was unable to warn others. Palming was just impossible as I was literally suffocating. Back then, I already knew from my Open Water courses that It was impossible to go up to the surface. I only had one solution left. I had to follow the advices I heard during the diving courses. I had to empty my lungs thoroughly by exhaling as much as possible and slowing down the pace of the inspirations. I had to calm down and to focus on my breathing. Yes, it sounds easy but it’s not.
A few seconds later it was already better, I manage to renew my air and my heart began to settle. My dive companions had meanwhile noticed my absence, had turned around and just found me still, quietly kneeling on the sand. I then indicated my shortness of breath and reassured others immediately with an OK sign. But when it happens to you, this is a very frightening feeling. Furthermore, after this experience, the rest of the dive is always more stressfull and during the hyperventilation, I asued already a quarter of my air. Being breathless during a dive is clearly not the best way to save air while scuba diving.
Already, it must be remembered that when you start diving, using the fins correctly is difficult and takes a lot of effort, so in consequence, it increase the air consumption. If you breathe too quickly in depth during a violent effort, you produce an overdose of carbon dioxide that accumulates in the lungs. Most of the divers don’t think of exhaling deeply from time to time to evacuate this toxic gas. Suddenly, the partial pressure of CO2 increases in the blood while that of oxygen decreases. Even if it is far from being the case, the brain analyzes the situation as critical and makes you feel very strongly this lack of air, the panic mode has just started, it is the beginning of the breathlessness. If you add the fact that when you learn scuba diving, everything can be a source of stress and, as a consequence, you can easily feel discomfort while breathing underwater.
The experience is terrible and frightening but, it is easy to get rid of it by following those few steps:
In just minutes everything is back to normal. If you really do not feel confortable or too scared after this experience, don’t hesitate to say it to the divemaster or instructor. There is no shame in stopping a dive.