Your body can withstand the stress of extreme pressure, such as that which is found deep underwater. You have total immunity to the physical dangers of compression and decompression, otherwise known as “the bends.” Your body maintains normal internal pressure no matter how dense the air or water is beyond your skin.
This adaptation offers no protection against de-pressurisation, such as that caused by exposure to space, nor does it supply you with oxygen. You can still asphyxiate if you do not have sufficient oxygen. Powers that alleviate your need to breath, or equipment that provides breathable air, function normally assuming that they, too, can survive deep-see pressures.