Conclusions:
This study suggests that a multitude of physical, cognitive and emotional symptoms persist for very long periods of time following chronic exposure to CO. The CO exposure need not produce altered consciousness at any time for this to occur. In fact, the CO exposure concentrations and COHb saturations are usually quite low, in the range previously thought incapable of producing lasting health harm in humans.
While a study such as described here has the inherent weaknesses of self-reporting errors and biases, it provides valuable clues to a condition until recently all but ignored by the medical community.
The amount of data and the resulting conclusions regarding chronic CO poisoning on this site are probably more than found anywhere else. Clearly, prolonged exposure to this insideous poison, even at what were previously thought to be low levels, is capable of producing many and varied residual health effects. Furthermore the incidence of such unpleasant and often debilitating effects is far higher than was previously believed by the medical and public health community, and can continue for a very long period of time.