The most important basic elements of life are oxygen and water. Tens of thousands of years ago, the oxygen content of the Earth’s atmosphere was 38%. Currently, due to considerable deforestation and high carbon emissions, the oxygen content of the atmosphere is 21% under optimal conditions. For example, in large cities this value can be as low as 18%. Such low oxygen levels can burden the human body significantly, which can lead to a constant state of oxygen-deficiency in the tissues. Generally speaking, it can be stated that human health is basically determined by the oxygen level in the body.