[PaulC]

I think that the theory goes something like this: that after most dives it is possible to detect micro bubbles in the diver's blood stream that do not give rise to acute symptoms but are abnormal nonetheless. A bend may be caused if the size of those bubbles increases to the point where they can cause identifiable damage: however the theory states that even if you do not show classic signs and symptoms of a bend there are still these abnormal micro bubbles in the blood. It is thought that a proportion of 'off-gassing' actually takes place this way with the gas circulating in the form of micro bubbles in the blood stream and not in solution.

I have come across the suggestion on more than one occasion recently that post dive fatigue is caused or contributed to by these micro bubbles. Although that isn't perhaps a bend as we know it it is a symptom of breathing compressed gas under pressure, according to that theory: perhaps that is why it has been labelled 'sub-clinical DCS'.

I wouldn't know enough about it to say one way or the other but it does seem to me (as John says) that breathing nitrox for a series of dives makes me feel less knackered afterwards.

Anyone with a deeper knowledge of this subject please post and let us know more - it must to an extent be a concern if physical symptoms are being caused by the after effects of diving, given the lack of data about the long term effects (i.e. 30+ years) of what we do!