Painful Memories
Posted By Divers Alert Network on 15 January 2008
By Dr Allan Kayle | visit DAN Online
Q: I get a headache about 10-15 minutes into my dive. It lasts throughout my dive but disappears within a few minutes of surfacing. What is it due to and what must I do?
A: You pose an interesting problem. Your headaches appear to be unrelated to descent, ascent or depth. The only constant factors are time - about 10-15 minutes into the dive - and the fact that pain disappears within a few minutes of surfacing.
Headaches usually follow a distinct pattern in each diver who experiences them. They can occur regularly during or after a dive, at the bottom, on ascent and, very commonly, immediately after surfacing.
Aside from the perennial diver hangover headache or a direct bang on the head during an ascent, the following are the usual causes of headaches in divers. Your headaches could fit some of these causes and I hope this article helps you.
Psychological Causes
Anxiety is a common cause of headaches in tense novice divers. It shows up as a classic tension headache, with pain over both sides of the head and at the back of the neck. It is due to insecurity about being exposed to a potentially dangerous underwater environment. With increasing experience and underwater skill, it invariably disappears.
New divers with a fear of losing their air supply under water often bite too tightly on the regulator mouthpiece. This may cause spasm of the temporalis muscles in the temples and produce headache. A malaligned bite or a filling that is riding too high may result in uneven stress of the joints between the jawbone and the skull. This will also cause headache when clamping a mouthpiece tightly between the teeth.
Physical Causes
Tight gear is another common cause of headache in inexperienced divers. Adjusting mask straps too tightly in the hope of avoiding mask leakage during the dive causes pressure right around the head, exactly like a very tight hat or glasses that are too small for the wearer. This pressure effect of the mask straps starts some minutes into the dive and gets worse the longer the dive. It is relieved by removing the mask after the dive and pain usually disappears rapidly.
Wetsuit collars fitting too tightly around the neck is another cause of headache. Tight collars compress the veins that drain blood from the skull and brain and can cause retention of carbon dioxide in the brain. This can precipitate a typical carbon dioxide headache. If the collar is very tight, compression of the carotid sinuses in the carotid arteries in the neck can occur with a reflex drop in blood pressure and even sudden unconsciousness - the so-called carotid sinus reflex. Headaches can also occur with wetsuits, straps or buoyancy compensators that are too tight-fitting around the chest and restrict easy breathing. This again can cause carbon dioxide build-up and headache.
Sinus squeeze causes headaches that are referred to the sinuses involved. Nasal and sinus allergy, polyps or infection can easily cause obstruction to the small openings between the sinuses and the nose. This makes it difficult or impossible for air to pass freely between the sinuses and nose and, with the increasing pressure of descent, Boyle's Law* operates and sinus barotrauma occurs.
The most common site of sinus squeeze is the forehead, relating to the frontal sinuses. Pain over one or both cheeks or even the upper teeth is referred from the maxillary sinuses. Pain in the eyeballs is due to ethmoid sinus squeeze, and pain at the back of the head on descent often relates to sphenoid sinus squeeze. The pain is usually relieved by ascent. The reverse can also occur. Compressed air trapped in a sinus after a successful descent will cause headache on ascent. Management is obviously avoidance of diving in the presence of significant nasal obstruction and having allergy or infection treated.
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