Objective: Hypoxia exposure, associated with changing metabolic rate and energy expenditure, is a general metabolic perturbation that might affect fuel utilization. Hypoxic training has been used to improve endurance in athletic performance for decades. Sufficient evidence has revealed that high-intensity interval exercise, a time-efficient strategy, has positive effects on eliciting metabolic health improvements in recent years. This study aimed to examine whether acute normobaric hypoxia and hypoxic highintensity interval exercise would be better to improve basal metabolic rate (BMR) and fat oxidization than normobaric normoxia and normoxic high-intensity interval exercise. Methodology: A single-blind 2·2 factorial design was employed in this study. Eight healthy males (Age: 23.5 ± 1.9 years, BMI: 22.6 ± 4.1kg/m2 ) from plain regions without regular exercise were recruited and randomly assigned into four trails: hypoxic highintensity interval exercise trail (HHIE), hypoxic rest-control trail (HCON), normoxic high-intensity interval exercise trail (NHIE), and normoxic rest-control trail (NCON). A bout of exercise or blank control (no physical exercise) were carried out at the same time of the day (between 18:00–22:00 p.m.) with 15.4% oxygen or sham hypoxia. For each exercise session, participants of HHIE and NHIE underwent all-out cycling exercise with 6-sec interspersed with 30-sec of rest, for 10 repetitions. Artery oxygen saturation (SaO2), rating of perceived exertion (RPE) and heart rate (HR) were monitored during exercise and consequent resting intervention. The values of BMR were measured in a fasting state with a supine position in the following mornings after trails accordingly. v Results: Repeated-measures ANOVA showed that HIE could increase the post-exercise oxygen consumption (p < .001) and energy expenditure (p < .001). In addition, the body could get recovery in the post-exercise observed period. However, no significant differences were found in following BMRs among the four trails. There was also no statistical significant interaction between oxygen levels and exercise patterns (p > .05). Conclusion: This study shows that acute HIE could elevate the post-exercise energy expenditure despite no effect is induced by hypoxia. Moreover, hypoxia or HIE has no effect on BMR in healthy males. Keywords: High-intensity interval exercise, hypoxic training, resting metabolic rate