Q: I understand that feeling tired after a dive may be a symptom of decompression sickness, but I almost always feel tired after diving. Should I be concerned?

A: The expectation of normal (ie, nonpathological) tiredness following diving varies from person to person. Factors such as individual fitness, thermal stress, gear constriction, diving skill, work completed during the dive, psychological stress (positive or negative) and distraction can all affect how tired one feels. While these variables make it difficult to quantify tiredness as a symptom of decompression sickness (DCS), unusual fatigue has long been documented in association with other symptoms of DCS.

The mechanism behind fatigue as a symptom of DCS remains elusive, although it is possibly a response to a cascade of physiological events taking place in various tissues. It could be through direct stimulation of nervous tissues or indirectly through the stimulation of other tissues. It is possible that the attention currently being directed toward identifying biochemical markers of DCS will help resolve the questions. In the meantime, it is reasonable to say that DCS represents a complex, multifocal response to a decompression injury. Unusual or ‘undue fatigue’ (that in excess of normal fatigue for a given individual and diving exposure) is a recognized symptom.

Q: I regularly suffer from a headache after diving. I do not suffer from migraine and do not suffer from a headache when I do short dives. What can be wrong? A: Chronically recurrent headaches after long dives can have numerous causes. Most are: 1. Accumulation of carbon dioxide in the blood caused by wrong breathing techniques. These headaches are very severe and last quite a long time.

2. Unfavourable diving position with overextension of the cervical spine. Often hardening of the neck muscles can be found.

3. Biting the mouthpiece of the regulator too hard can lead to overstressing the chewing and postural neck muscles and can therefore also lead to severe headaches, which should, however, resolve swiftly after the dive.

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