Hyperbaric oxygen therapy improves peripheral insulin sensitivity in humans

Aim Hyperbaric oxygen therapy is known to reduce fasting blood glucose in individuals with Type2 diabetes. However, the mechanisms of this effect are not clear. The aim of this study was to determine whether peripheral insulin sensitivity by hyperinsulinaemic euglycaemic clamp is increased in patients presenting for hyperbaric oxygen therapy. Methods Participants were non-obese individuals without Type2 diabetes (n=5) or obese patients with Type2 diabetes (n=5). Patients were given 100% oxygen at 2.0 absolute atmospheres for 2h, six sessions per week for 5weeks. Results Peripheral insulin sensitivity was increased in the whole cohort (P=0.04). Subsequent analysis revealed that this was significant at both treatment3 (+37.3±12.7%, P=0.02) and treatment30 (+40.6±12.6%, P=0.009). HbA _1c was significantly reduced in subjects without diabetes only (P<0.05). Conclusion Insulin sensitivity increased within 3days of hyperbaric oxygen treatment and this was maintained for 30 sessions. This increase in insulin sensitivity is equivalent to that observed following moderate weight loss. The mechanisms underlying the insulin-sensitizing effect of hyperbaric oxygen require further elucidation.