Headaches and Diving.

More than one person has expressed his or her intention to give up the sport because of recurrent headaches, and this would be an unfortunate and often unnecessary response.
At least some dive related headaches can be avoided with simple changes to diving patterns.
In discussing headaches and diving, it is useful to classify them according to their temporal relationship to diving, that is whether they occur before, during or after the dive.

Headaches beginning prior to diving.
Headaches which are present prior to a dive (assuming that it is not a repetitive dive) are obviously unlikely to be related to diving. Nevertheless, divers with a headache prior to their dive are less likely to perform as well physically or mentally.
In general pre-dive headaches should deter the diver from entering the water, and may herald a significant medical condition.
Medical advice should be sought if a headache is unusually severe, of unusual quality, associated with other symptoms (especially neurological symptoms, stiff neck or exacerbation by bright lights), or fails to resolve within a reasonable time.
At least some of the causes of pre-dive headaches may have particular significance in the diving environment, and these are discussed below.

Perhaps one of the most common causes of pre-dive headaches is the hangover!

While some might say that this is an excessively cynical view, the fact that most diver of a few years standing would be able to relate stories of divers entering the water while hungover. Hungover divers are most unlikely to perform well physically or mentally. Further, the physiological changes underpinning the hangover may predispose the diver to Decompression illness (DCI)
In particular, hangovers are associated with a variable degree of dehydration secondary to the diuretic effects of alcohol. This dehydration can be exacerbated in the diver standing around in a hot wetsuit (or Drysuit), motion sickness (with vomiting), breathing in dry air from the cylinder and the diuretic effect that inevitably accompanies immersion (ever wondered about the reliably inconvenient urge that always occurs whilst diving)
For various reasons dehydration is likely to make an episode of DCI both more likely and more serious. For this reason alone, diving while hungover is strongly discouraged.

Divers should however remember to take fluids between dives as this will prevent dehydration which in turn may help to reduce the risk of possible headaches.

Another significant cause of pre-dive headaches is the headache associated with a cold or flu like illness. Symptoms of a cold are strongly predictive of problems with equalisation in ears and sinuses and divers should not enter the water if such a problem is suspected. This is particularly true if the headache is localised to the ears and sinuses. Ears and sinus pain is suggestive of infection and almost certain congestion of these areas. The sinuses most often affected are the Frontal and Ethmoid sinuses (see Lecture 4)

Headaches beginning during diving

  1. Headaches beginning during descent

    2. Headaches beginning during descent are most likely to be due to the effects of pressure changes to the ears and sinuses. Most divers are familiar with the discomfort experienced if there is any difficulty equalising the pressure in the middle ear with the surrounding environmental pressure during descent.
    Difficulty equalising usually indicates congestion of the Eustachian Tube which links the back of the throat to the airspace of the middle ear (behind the ear drum), and is sufficient reason for terminating the dive. Divers should not try to ‘push through’ increasing ear pain during descent since this may result in bleeding into the middle ear and damage to the ear drum itself.
    The likelihood of ear problems can be minimised by descending in an upright position, beginning to equalise early and often (not waiting for any discomfort) and by controlling the descent by holding on to a shotline if one is available

    Sinus discomfort is less common than ear pain, but can be quite debilitating. It is usually due to congestion of the tubes that link the sinus with the nose, thereby preventing equalisation of the pressure inside the sinus with that of the surrounding environment. As above, when this problem is encountered it is better to terminate the dive.

    Divers who dive without a hood sometimes report a severe generalised headache on initially entering the water and starting the descent, particularly if the water is very cold. These headaches usually pass within a few minutes as the diver acclimatises themselves to temperature. These headaches are thought to be due to the effects of cold on the local blood vessels to the scalp, although this is not certain.
    The best way of avoiding them is to wear a hood if the water is cold. It is worthwhile making sure that the hood covers the forehead all the way down to the mask since quite severe headaches can be generated by exposure of even a small are of forehead to cold water.

  2. Headaches beginning during bottom time

    3. The most common cause of headache which is not present during descent, but which onsets after some time on the bottom, is a build up of excess carbon dioxide (CO2).
    The body’s cells require oxygen (O2) for energy production and in doing so produce CO2 as a by-product. CO2 produced by the cells is carried back to the Lungs in the blood and is exhaled during our normal breathing. The rate of CO2 elimination from the body is determined by our breathing rate. The faster we breathe the more CO2 we eliminate. The need to eliminate CO2 is the reason we pant during exercise.
    Underwater, our ability to ventilate our lungs (and therefore to eliminate CO2 ) is changed somewhat. The increased density of the air makes our regulator less efficient and the air is therefore harder to breathe. There are some complex physiological changes in the lungs and airway which together with the reduced efficiency of the regulator, substantially reduces our ability to ventilate. The net result is that if exercise too hard underwater, our body may not be able to eliminate CO2 at the same rate it is produced, and accumulation can occur. This is known as Hypercapnia or carbon dioxide poisoning).

    Accumulation of CO2 can cause several distressing symptoms.
    The diver will usually feel short of breath and may adopt a pattern of rapid shallow breathing. This breathing pattern is likely to worsen the problem. The diver may feel lightheaded or even dizzy.

    Nitrogen Narcosis can be significantly worsened by Hypercapnia.

    But the most common symptom of over exertion with CO2 accumulation, is a severe generalised headache occurring towards the middle or end of the dive. This headache is caused by the CO2 induced changes in the size of blood vessels in the brain and will commonly persist for a period after the dive. Usually simple painkillers such as Aspirin or Paracetomol will be of little benefit. It is often claimed that breathing Oxygen after the dive will relieve the headache.

    Although this may have seemed effective is some instances, it is probably fair to say that the most significant effect of Oxygen administration in such cases is to diminish the O2 supply available for future dive sites if a real emergency arises.

    The best way of avoiding CO2 headaches is to avoid excessive exertion underwater. Classically, over exertion occurs on dives where the goal of the dive is stripping as much biomass as possible from the marine environment in as short a time as possible ( or trying for that coveted bit of brass from a wreck).

    Vigorous exercise should be avoided whilst diving, relax, swim slowly and enjoy your dives. If you do develop a headache during a dive, perhaps with lightheadedness and a mild feeling of shortness of breath, stop, relax, breathe slowly and deeply and consider ending the dive, especially if the symptoms do not settle.

    Another cause for headache during a dive is migraine.
    Some migraine sufferers find that diving precipitates their headaches. Since these events can be quite debilitating, and since the headache may occasionally be accompanied by neurological symptoms that may mimic DCI, it is generally recommended that those who suffer migraines should not dive.

  3. Headaches beginning during ascent.

    4. The most common cause of headaches caused during the ascent is the so-called ‘reverse squeeze’ in the ears and/or sinuses. As with ears or sinus pain during descent, this is caused by congestion of the tubes linking the middle ear to the throat or the sinuses to the nose. The result is that air pushed into the ear or sinus during equalisation while descending cannot escape due to blockage of any congestion, and will expand during ascent ‘pressurising’ the space. This is a relatively un-common problem. It can however be considerably distressing since attempts to get to the surface increase the pain. The ascent should be stopped and the diver should descend if possible until the pain has eased, after which a slow ascent should begin.
    During the ascent, manoeuvres such as wiggling the jaw from side to side or swallowing may help open the blocked tubes. The diver should not attempt to clear the ears by pinching the nose and blowing as on the descent, as this may pressurise the ear further.

  4. Headaches beginning after a dive.
    Some of the headaches described above may persist after a dive and if these events are protracted or severe, it would be wise to seek medical advice, particularly where the ears are involved.

    Headaches can also begin after a dive and recompression facilities sometimes receive calls from divers concerned that their headaches are the symptoms of DCI.
    While headaches can be part of the symptoms of DCI it is unlikely that any recompression facility would make the diagnosis of DCI on a headache alone. There would almost certainly be other symptoms to support any diagnosis of DCI.

    Obviously if other symptoms were present or the diver had any particular reason to be concerned, he or she should always contact a recompression facility for advice.
    Most headaches after a dive will be due to other causes such as fatigue, sunstroke or dehydration.

     

    This article is partly taken from a similar article by Dr Simon Mitchell who kindly gave his permission to use part of his original article.

    The original article appeared in the Sportdiving Magazine (Australia)