The ability to descend to the deepest depths of the earth’s largest water sources provides a number of useful benefits, ranging from research to recovery of some of humanity’s most precious treasures. Whether you are scuba diving for a specific purpose or just as a leisure activity, there are a number of rules and regulations that must be strictly adhered to for safe diving.
While breathing gas cylinders provide much needed O2, the deeper you dive, the greater the pressure that is created, which means very specific partial pressures of O2 have to be maintained. One of the potential outcomes of not adhering to these parameters is oxygen toxicity.
Oxygen toxicity occurs when your oxygen concentration is too high for the depth you are at and the specific conditions you are diving in. There are a wide range of symptoms of oxygen toxicity which range from nausea and vomiting to having trouble breathing and dizziness. Symptoms which, quite obviously, you don’t ever want to experience at depth. The most severe consequence of oxygen toxicity, however, is convulsion. When a convulsion is experienced at depth, it almost inevitably results in drowning or an arterial gas embolism.
The problem with O2 levels is that they are dependent on a number of variables, some of which you know and can monitor, some of which you can’t. Your depth and exposure time are variables you can monitor, but your metabolic rate is also a factor and you can’t monitor that as well.
Shivering is a form of exercise which is going to increase your metabolic rate, so temperature also plays a part in regulating appropriate O2 levels. In addition, there are a wide variety of health issues such as thyroid disease or certain medications that effectively mimic adrenaline that will play a role in maintaining appropriate O2 levels.
The primary reason for Dalton’s law (the total pressure exerted by a gas mixture is equal to the sum of the partial pressures of the different gases in the mix) is to help avoid oxygen toxicity. When it comes to O2 levels, it is important to do very precise and accurate calculations, which take as many factors as possible into account. Not doing so can have very severe and possibly even fatal consequences.