As for oxygen, your brain is naturally the most demanding organ, it uses up to 20% of your total oxygen consumption as you sit and read these lines, despite the fact that it only represents 2% of your total body weight. In addition to being the greatest consumer of oxygen in the body it is also the most sensitive to changes in oxygen level. If for some reason you are low on oxygen, the brain will be the first to suffer damage.
The first set of conclusions appeared after the first 20 years of the study and showed that lung volume, the vital capacity (VC), was the best parameter apart from age to predict when a subject would become ill or die. The vital capacity steadily declines with age, and the relationship between vital capacity and mortality is inversely related – the smaller the vital capacity, the shorter amount of time you have to live.