Hypoxic high-intensity interval training was not superior to normoxic HIIT for improving cardiorespiratory fitness (V̇o2peak +14.2% vs +12.1%) in individuals with overweight and obesity.
RCT (n=31)
Does hypoxic high-intensity interval training improve cardiorespiratory fitness and cardiometabolic health status compared with normoxic HIIT in individuals with overweight and obesity?
In individuals with overweight and obesity, combining normobaric hypoxia with high-intensity interval training was not superior to normoxic HIIT for improving cardiorespiratory fitness, despite allowing for a lower absolute training workload.
Absolute Event Rate: 14.2% vs 12.1%
Combining moderate-intensity exercise training with hypoxic exposure may induce larger improvement in cardiometabolic risk factors and health status compared with normoxic exercise training in obesity. Considering the greater cardiometabolic effects of high-intensity intermittent training (HIIT), we hypothesized that hypoxic high-volume HIIT (H-HIIT) would induce greater improvement in cardiorespiratory fitness and health status despite a lower absolute training workload than normoxic HIIT (N-HIIT) in overweight/obesity. Thirty-one subjects were randomized to an 8-week H-HIIT 10 male and 6 female; age: 51.0 ± 8.3 years; body mass index (BMI): 31.5 ± 4 kg·m −2 or N-HIIT (13 male and 2 female; age: 52.0 ± 7.5 years; BMI: 32.4 ± 4.8 kg·m −2 ) program (3 sessions/week; cycling at 80% or 100% of maximal workload for H-HIIT and N-HIIT, respectively; target arterial oxygen saturation for H-HIIT 80%, Formula: see text ∼0.12, i.e., ∼4,200 meters above sea level). Before and after training, the following evaluations were performed: incremental maximal and submaximal cycling tests, pulse-wave velocity, endothelial function, fasting glucose, insulin, lipid profile, and body composition. Maximal exercise (V̇o 2peak : H-HIIT +14.2% ± 8.3% vs. N-HIIT +12.1 ± 8.8%) and submaximal (ventilatory thresholds) capacity and exercise metabolic responses (power output at the crossover point and at maximal fat oxidation rate) increased significantly in both groups, with no significant difference between groups and without other cardiometabolic changes. H-HIIT induced a greater peak ventilatory response (ANOVA group × time interaction F = 7.4, P = 0.016) compared with N-HIIT. In overweight/obesity, the combination of normobaric hypoxia and HIIT was not superior for improving cardiorespiratory fitness improvement compared with HIIT in normoxia, although HIIT in hypoxia was performed at a lower absolute training workload.
Ghaith et al. (Mon,) conducted a rct in Overweight and obesity (n=31). Hypoxic high-volume high-intensity interval training (H-HIIT) vs. Normoxic HIIT (N-HIIT) (cycling at 100% of maximal workload) was evaluated on Maximal exercise capacity (V̇o2peak) improvement. Hypoxic high-intensity interval training was not superior to normoxic HIIT for improving cardiorespiratory fitness (V̇o2peak +14.2% vs +12.1%) in individuals with overweight and obesity.