Oh, Bolas!

Fat divers know that they are a greater risk to decompression because fatty tissue absorbs nitrogen gas in higher densities while releasing it more reluctantly, just as smokers know that their lungs could rupture more easily during ascent. But what is insufficiently known is that belly fat take space that would otherwise have been used for breathing. A wetsuit furthermore exerts pressure on the chest, and these two factors make that fat people run out of breath very quickly. They can seem fit and strong in non-aerobic exercise (such as lifting) but fail badly when air is needed in aerobic exercise such as swimming back to the boat in a current. You can't be fat as a good underwater photographer!