Another study further confirmed the hypotensive effect of IH conditioning in patients with stage 1 hypertension, confirmed that hypoxic adaptation combined with exercise produced a better and longer-lasting hypotensive effect than oral antihypertensive drugs alone, and found that the hypotensive effect of hypoxia correlated with elevated levels of nitric oxide (NO) and hypoxia-inducible factor-1alpha (HIF-1α) (Muangritdech et al., 2020). This evidence concerns the gene HIF1A and hypertensive disorder.