Plasma glucose responses in recreational divers with insulin-requiring diabetes

Insulin-requiring diabetes mellitus (IRDM) is commonly described as an absolute contraindication to scuba diving. A 1993 Divers Alert Network survey, however, identified many active IRDM divers. We report on the plasma glucose response to recreational diving in IRDM divers. Plasma glucose values were collected before and after diving in IRDM and healthy control divers. Time/depth profiles of 555 dives in IRDM divers were recorded. IRDM divers had been diving for a mean of almost nine years and had diabetes for a mean of over 15 years. No symptoms or complications related to hypoglycemia were reported (or observed). Post-dive plasma glucose fell below 70 mg x dL(-1) in 7% (37/555) of the IRDM group dives compared to 1% (6/504) of the controls (p<0.05). Moderate levels of hyperglycemia were also noted in 23 divers with IRDM on 84 occasions. While large plasma glucose swings from pre-dive to post-dive were noted, our observations indicate that plasma glucose levels, in moderately-controlled IRDM, can be managed to avoid hypoglycemia during routine recreational dives under ordinary environmental conditions and low risk decompression profiles.