Headaches are never any fun and no matter what, a headache while diving can ruin what would have been a perfectly good dive. However, if the headache is a migraine, then there may be some other considerations involved. Migraine headaches are very common and at least half of people worldwide will experience a migraine headache at some point throughout their lives. In general, migraines can range in severity from mild to severe and there are a variety of signs and symptoms that can accompany and even precede the onset of a migraine. It is important for an individual to know these signs and symptoms well so that he or she can detect when a migraine is about to happen.
If a person gets migraine headaches, this does not mean that they cannot dive. In fact, there is no evidence to suggest that there is a problem diving for those who suffer migraines and there is no indication that there is an increased incident in migraines in those who do dive. Having said this, since diving causes an increase of carbon dioxide in the body due to decreased ventilation and occasionally the holding of one's breath. This increase in carbon dioxide causes vasodilatation in the brain, which can cause the onset of a migraine headache. In fact, it has been proven that in severe cases of migraines, hyperbaric oxygenation therapy can be used as an effective treatment simply because it acts as a powerful vasoconstrictor, relieving the brain of its affliction. An increase in barometric pressure can also cause a migraine to occur.
The diver needs to be aware of possible triggers for their migraines. If exercise is one of the things that triggers a migraine and if the migraines tend to be serious in nature, then the diver must take the necessary precautions. If you have been diving in the past and have had a migraine start while you were diving, then consideration should be given to whether or not you should dive. Serious migraines can cause nausea, vomiting, and even loss of vision and paralysis in extreme cases. These people should not dive because any one of these symptoms can cause a person to drown or otherwise have an emergency while underwater.
Of course, there are many other reasons why a headache might appear and this should be taken into consideration, even for the migraine sufferer. After all, tension and stress, sinus and ear infections, a cold, mask squeeze, dental problems, gas toxicity, decompression illness, and many more things can cause a headache while in the water. So if a headache does come on while you are diving, it is best to get out of the water rather than assume it is a migraine and keep diving. This is due to the chance that the headache may be the result of something else and it is important that you be sure you don't have a situation more serious than a migraine on your hands.
All in all, there is not very much data on migraines and diving so caution is always advised. If you have mild and/or infrequent migraines or if you have gone a number of years without getting a migraine, then you are probably safe to dive. However, if you do get them frequently or severely and you know the warning signs and can tell one is about to come on; avoid diving for the duration of the migraine. If you experience a rise in severity of your migraines with diving or if you tend to have serious migraines that can disrupt your vision and/or your ability to remain conscious and cope with the underwater environment, then you might need to avoid diving. The best thing to do is to consult a diving physician if you are unsure; don’t take any unnecessary risks!