| All very good advice there.
Regarding the headaches - very often I see divers having the wrong attitude in the water. A position that has them "looking at the sky" if they were on dry land.
They don't realise it but they are constantly putting a strain on their neck muscles as they hold this attitude.
Check yours and ask if you have a relaxed neck position.
BTW if you tend to yawn a lot on the boat after a dive, then your breathing has been incorrect.
Seadeuce |