The tranquil in underwater world

The tranquil underwater world may put your mind at ease, but for many divers, the hours that follow can be one big headache. Don't let throbbing pain put a damper on your next dive.
Loosen up: Your hood is tight. Your wetsuit is tight. Your mask is tight. You've got your jaw in a death grip around your regulator. Pay attention during the dive to how you hold the regulator in your mouth: Are you clenching it? Bite down gently on your mouthpiece. And a well-fitted mask doesn't need to be cinched within an inch of its life. The more restricted and constricted you are, the more likely you are to emerge with a headache.
Check your tank position. If the back of your head keeps hitting your first stage, adjust the position of the cylinder as needed.
Breathe Carbon dioxide buildup is one of the most common causes of post-dive headaches. CO2 can only build up when you don't get enough oxygen. So it's common in people who take small sips off their regulator or "skip breathe" by pausing after every inhalation and holding their air before exhaling. Avoid CO2 build-up headaches by taking full, even breaths off your regulator.
Drink up. Dehydration will make you headachy in a hurry. Between the hot sun and the long days on and under the water, it can be easy to let your fluid intake slide. Have a fresh, full bottle of H2O with you at all times. And avoid alcohol. Too much alcohol leads to dehydration and electrolyte imbalance, leaving you headachy, fuzzy-headed, queasy and fatigued the next day. Drink Up explores the negative aspects of dehydration in more detail.
Clear those sinuses. Sinus barotrauma or "squeeze" is another common cause of post dive head pain. These skull crushers are especially common in divers who have problems equalizing. When you shift depths without properly equalizing, your sinuses may take a squeeze causing a shot of pain across your forehead and eyes. This one requires medical help. Once the condition is resolved, you'll need to figure out a way to equalize successfully. Be sure to descend and ascend very slowly, equalizing every step of the way.