Hypoxic training improves blood pressure, nitric oxide and hypoxia-inducible factor-1 alpha in hypertensive patients

Purpose To examine the effects of intermittent hypoxic breathing at rest (IHR) or during exercise (IHT) on blood pressure and nitric oxide metabolites (NOx) and hypoxia-inducible factor-1 alpha levels (HIF-1 alpha) over a 6-week period. Methods 47 hypertensive patients were randomly allocated to three groups: hypertensive control (CON:n = 17; IHR:n = 15 and IHT:n = 15. The CON received no intervention; whereas, IH groups received eight events of hypoxia (F(I)O(2)0.14), and normoxia (F(I)O(2)0.21), 24-min hypoxia and 24-min normoxia, for 6 weeks. The baseline data were collected 2 days before the intervention; while, the post-test data were collected at days 2 and 28 after the 6-week intervention. Results We observed a significant decrease of the SBP in both IH groups: IHR (- 12.0 +/- 8.0 mmHg,p = 0.004 and - 9.9 +/- 8.8 mmHg,p = 0.028, mean +/- 95% CI) and IHT (- 13.0 +/- 7.8 mmHg,p = 0.002 and - 10.0 +/- 8.4 mmHg,p = 0.016) at days 2 and 28 post-intervention, respectively. Compared to CON, IHR and IHT had increased of NOx (IHR; 8.5 +/- 7.6 mu mol/L,p = 0.031 and IHT; 20.0 +/- 9.1 mu mol/L,p < 0.001) and HIF-1 alpha (IHR; 170.0 +/- 100.0 pg/mL,p = 0.002 and IHT; 340.5 +/- 160.0 pg/mL,p < 0.001). At 2 days post-intervention, NOx and HIF-1 alpha were negatively correlated with SBP in IHT. Conclusion IH programs may act as an alternative therapeutic strategy for hypertension patients probably through elevation of NOx and HIF-1 alpha production.