Intermittent hypoxia as an interventional strategy for impaired fasting blood glucose: a systematic review

The aim of this systematic review is to analyse the current evidence reported in the literature on the efficacy of resting in normobaric hypoxia as a potential intervention for patients with impaired fasting blood glucose. Available databases was searched, under the PRISMA guidelines, throughout to the end of August 2017. A total of four empirical studies (out of 3281 filtered) were identified as eligible for the review. Two studies were on the acute effects of one-hour exposure to moderate hypoxia, and reported a reduction of blood glucose by 0.74 to 2.1 mM. The other two studies were on the effects of repeated exposure with nine to ten sessions in two to three weeks, however did not shown sustained decrease in fasting blood glucose. These studies employed selfcontrolled design with relatively small numbers of participants (n= 6-18). Similar findings were also reported in studies on the effects of exercising in hypoxia with single bout or several weeks of intervention. Further research, particularly randomised controlled clinical trials, is required to determine the efficacy and hormetic dosage range of long-term IH intervention for pre-diabetes and type 2 diabetes, and to elucidate the underlying mechanisms of the treatment effects.