Our previous study shows that normobaric hypoxia training with calorie restriction has an additive improvement on weight loss and blood pressure in obese individuals, thus hypoxic training could be a tool to treat obesity and associated comorbidities. However, the relevant mechanism is unclear. Given the complexity of hypoxia, it still needs to extend our knowledge regarding hypoxia as a therapeutic approach to improve health outcomes in different populations. High-intensity interval exercise (HIE) has been considered a time-efficient approach to improve aerobic fitness. Combination of HIE and hypoxia seems to have a potential influence on metabolism. Yet, our recent study didn’t find any differences in physiological responses caused by acute HIE in hypoxia simulated 2500 compared to normoxia. A low dose of hypoxia might be the potential factor to cause such a result. Thus, a relatively higher altitude, eg. 5000 m, may have a different metabolic response when compared to 2500 m hypoxic exposure/exercise. Our hypotheses are 1) the response of hypoxia exposure (5000 m) is different from that of normoxia on metabolism, and 2) a single bout of HIE under hypoxia (5000 m) has a different effect on metabolism when compared to HIE under normoxia.