[PureConfidence]

Can I obsorb oxygen through my skin?

[JSThom]

I've heard something like that when skydiving, a person can 'absorb' oxygen through the skin in a condition like that so to an extent I believe you can.
I'm not certain on that, just something I remember hearing at some point.

[Lost-in-Science]

Yes, passively <1% of your body's oxygen content is absorbed through your skin from the atmosphere. However, the amount is far from being enough to keep your body alive. To give a rough idea without actual figures, the entire surface area of your skin is approximately 1-2 square meters. In comparison of all of your lung's alveoli having a represntative area of approximately 70-90 square meters. This huge surface area is essential just to bea able to absorb enough oxygen even with the process of lung ventilation.

Fundamentally it is a ratio between the gas exchange surface area and the amount of oxygen required to sustain life which can be direcctly correlated with the size (and shape) of the organism.

Frogs, for example, do have a pair of lungs being half terrestrial. When sedantary a frog's metabolism (therefore oxygen requirement) is low enough it can survive using just its skin as a gas exchange surface, a passive process and so not requiring any energy. When the frog starts to move again and its metablic rate increases it will start the energy inefficient process of breathing to maximise oxygen absorption.

I recognise this is not an entirely comprehensive answer, but I hope it answered your question.