I recently went snorkeling in Mexico. Our leader took us deep inside a cenote where there wasn't much oxygen. I was breathing deep already from swimming through there, I was cold, and then we had to dip under the water to go into the last cave, and I came up trying to catch my breath but I could not since there was a lack of oxygen. I tried to stay calm, but I was worried. She took us back, and when we got out of the water, my fingers felt like they were going numb and they were tingling. Some said maybe it was because they were cold, but they were not cold to the touch. One said it was from hyper-ventilation. Does anyone know what this would be caused from?