CONTROL OF BLOOD-GLUCOSE IN A GROUP OF DIABETIC SCUBA-DIVERS

A preliminary study to examine the hypothesis that the ability of well -controlled (defined as no hypoglycemic episodes within the last 12 mo ., HbA(1c) < 9.0%, and none of the long-term complications of diabetes type I) diabetic scuba divers to control their serum glucose and dive without becoming hypoglycemic during a simulated dive to 27 meters of seawater in a controlled environment is impaired. An open, controlled , crossover study compared blood glucose levels, hematocrits. and hema tologic cell counts in a group of eight type I diabetic scuba divers t o those from eight age-and sex-matched, normoglycemic control scuba di vers. Each diver did one simulated dive and one control exercise on th e surface on 2 consecutive days. The simulated dive was done to depth of 375 kPa in a hyperbaric chamber; the control exercise was done at a mbient pressure. The order of the dive and the control exercise was ra ndomized. No statistically significant differences were observed betwe en serum glucose levels in the diabetic divers measured during the sim ulated dive to 375 kPa vs. the serum glucose levels in the diabetic di vers measured during the control exercise at the same time points. All divers with type I diabetes remained free of symptoms and signs of hy poglycemia throughout the course of the trial, and no diabetic subject had a serum glucose less than 4 mmol/liter before the end of the tria l. As the sample size was small, larger studies including subject with type II diabetes will be necessary to extend these results to the dia betic diving population at large. The authors conclude that, contrary to advice issued by most diving agencies to scuba divers, it may be sa fe to allow well-controlled subjects with type I diabetes with no long -term complications to undertake scuba diving, and that high partial p ressures of oxygen do not seem to lower serum glucose levels significa ntly in the diabetic diver during the dive.