Rebreathing-induced hypoxemia improves glucose tolerance in adults with type 2 diabetes

Hypoxia stimulates glucose uptake in isolated skeletal muscle through an insulin-independent pathway. Intermittent hypoxia can lower glucose concentration in adults with type 2 diabetes, but its application remains limited by the use of gas tanks to induce hypoxia. The aim of this study was to examine the effect of rebreathing-induced hypoxia on glucose and insulin responses to an oral glucose tolerance test in adults with type 2 diabetes. Ten adults with type 2 diabetes performed an oral glucose tolerance test during either rebreathing-induced hypoxia or spontaneous breathing. The glucose and insulin responses to the oral glucose tolerance test did not differ between rebreathing-induced hypoxia and spontaneous breathing. However, participants who achieved hypoxemia, defined as an oxygen saturation nadir below 90%, during rebreathing-induced hypoxia (n = 5) showed lower glucose concentrations and glucose area under the curve (AUC) (20,376 ± 553 vs. 24,346 ± 639, p < 0.01) than participants who achieved an oxygen saturation nadir above 90% (n = 5). Interestingly, body weight was strongly correlated with oxygen desaturation (r = -0.87, p < 0.01) and glucose AUC (r = -0.81, p < 0.01) during rebreathing-induced hypoxia. Rebreathing-induced hypoxia may represent a promising strategy to improve glycemic control in adults with type 2 diabetes and coexisting obesity.