Previous DCS with residual neurological disturbances . These people should not resume diving. Fatigue is also a subtle symptom of decompression sickness. Exertion during the deep part of the dive is a risk factor. Other studies have not borne this out.
Older divers have a higher percentage of body fat.
Greater age and higher fat content are traditionally associated with increased incidence of DCS but the evidence is not consistent, recent reports showing no relationship. Good physical fitness increases perfusion and ensures good gas exchange. Exercise at depth is detrimental, increasing nitrogen uptake. Exercise while decompressing is beneficial. Exercise at depth increases nitrogen uptake and is detrimental.