Short bouts of hypoxia improve insulin sensitivity in adults with type 2 diabetes.

Abstract

Hypoxia stimulates glucose uptake independently from the action of insulin. The purpose of this study was to determine the effect of intermittent hypoxia, consisting of alternating short bouts of breathing hypoxic and room air, on glucose concentration, insulin concentration, and insulin sensitivity during an oral glucose tolerance test in adults with type 2 diabetes and adults with normal glycemic control. Nine adults with type 2 diabetes (two women, HbA1c: 7.3±1.5%, age: 52±13 years) and nine adults with normal glycemic control (four women, HbA1c: 5.4±0.1%, age: 24±4 years) performed a 2-hour oral glucose tolerance test on two separate visits to the laboratory. Following ingestion of the glucose drink, participants were exposed to either an intermittent hypoxia protocol, consisting of eight 4-min hypoxic cycles at a targeted oxygen saturation of 80% interspersed with breathing room air to resaturation, or a sham protocol consisting of eight 4-min normoxic cycles interspersed with breathing room air. Intermittent hypoxia did not attenuate the increase in glucose concentration but attenuated the increase in insulin concentration in response to an oral glucose tolerance test in comparison with the sham protocol in adults with type 2 diabetes. Insulin sensitivity was greater during intermittent hypoxia in comparison with the sham protocol in adults with type 2 diabetes (0.043±0.036 vs. 0.032±0.046 μmol/kg/min/pmol, p=0.01), but did not change in the control group (0.122±0.015 vs. 0.128±0.008 μmol/kg/min/pmol, p=0.12). In conclusion, intermittent hypoxia improved insulin sensitivity in adults with type 2 diabetes.