Is There a Need for Sodium During Endurance Exercise?

The skin can hoover up excess sodium and then release it back into the blood at various times for various reasons. There have been suggestions in the past that that will actually mean that you don't need to consume sodium during exercise because you can release this sodium back into the water. But what we now understand about this sodium and its binding within the skin is that it's bound to these structures and it's released to regulate volume rather than osmolality or the sodium.