Ten nights of moderate hypoxia improves insulin sensitivity in obese humans - LeCoultre et al. (2013)
Ten nights of moderate hypoxia (15% O2) decreased the weight and fasting blood sugars of obese participants
Whole-body insulin sensitivity was also improved, as indicated by increased glucose disposal rates
The Breathing Diabetic Summary
This study was motivated by confounding results in previous research. For example, it is known that tissue hypoxia leads to insulin resistance. However, we have also seen that intermittent moderate hypoxia can increase glucose tolerance and improve insulin sensitivity. Populations living at high altitude also experience less insulin resistance than those living at sea level. So, this study aimed to see if sleeping in moderate hypoxia would improve insulin sensitivity in obese participants.
The participants spent approximately 10 hours a night in moderate hypoxia for 10 nights. Moderate hypoxia was defined as O2 at 15%. We know from Navarrete-Opazo and Mitchell (2014) that the therapeutic range of hypoxia is between 9-16% O2. Thus, 15% is on the upper end of the therapeutic range and definitely qualifies as “moderate.”
The results of this experiment were pretty impressive. The patients lost weight and decreased their fasting blood sugar from just 10 nights of moderate hypoxia. Their insulin levels were unchanged, meaning that their insulin sensitivity had increased (the same amount of insulin with a reduced fasting blood sugar equals better insulin sensitivity). They also measured something called the glucose disposal rate, or GDR. They found that at both high and low levels of insulin, the GDR of the patients was significantly increased, again revealing higher insulin sensitivity.
Overall, this study highlights the usefulness of moderate hypoxia for increasing insulin sensitivity. Although most of us probably don’t have the resources to sleep in moderate hypoxia every night, we will see in other studies that practicing intermittent hypoxia can also improve insulin sensitivity. Thus, the take home message is that moderate hypoxia might have therapeutic benefits for diabetics suffering from insulin resistance.
VIRGILE LECOULTRE, COURTNEY M. PETERSON, JEFFREY D. COVINGTON, PHILIP J. EBENEZER, ELIZABETH A. FROST, JEAN-MARC SCHWARZ, and ERIC RAVUSSIN, (2013) Ten Nights of Moderate Hypoxia Improves Insulin Sensitivity in Obese Humans, Diabetes Care, 36, e197-e198.