Free diving and holding your breath.

[canadageek]

when I experience pressure differences (diving/multiple flights) I get this horrible sensation in my forehead that is like something is stinging me, and it hurts like hell. after 2 consecutive flights, it also builds to a feeling of pressure behind my eyes. any clue on what this is and how i can fix it? I love both these things, and it suxks

 

[TheSlamma]

You should practice apnea in a pool (with a friend there) before you head out to open water.

 

[JulesMaximus]

Its the CO2 in the blood. Letting out air is going to make you feel better, but its going to deprive you of any oxygen left in your lungs.

Best way to do it is hyperventilate with long deep breaths for 20 sec or so then take a final big dose of 100% oxygen. This will get much of the CO2 out of the blood and you will feel better longer.

Agreed. Letting out air while you're under will make you less buoyant so you won't be able to float back to the surface.

Relax while you're under and conserve as much energy as possible. Also, be sure to leave yourself enough time to get back to the surface.

I've spent a lot of time snorkeling in water as deep as 15-20'. Once off of Catalina island I was snorkeling near a class of scuba noobs and one guy started to panic, I think he was afraid of the kelp and/or drowning. It was kind of scary being around him at that moment because people can be unpredictable when they panic.

 

[YOyoYOhowsDAjello]

Jello I am dissapoint!

I guess I can't be the ATOT MVP then