Effects of exercise interventions in hypoxic environment on cardiovascular function and maximal power output in obese or overweight individuals: a systematic review and meta-analysis

초록

Objective To compare the effects of normobaric hypoxic exercise versus normoxic exercise on improving cardiopulmonary and cardiovascular function and maximal power output in overweight and obese individuals, thereby providing evidence-based support for exercise prescription and public health interventions. Methods Following the PRISMA guidelines, randomized controlled trials examining the effects of exercise interventions under hypoxic conditions on cardiopulmonary and cardiovascular function or exercise capacity in individuals with overweight or obesity were retrieved from databases comprising PubMed, the Cochrane Library, Ovid, Web of Science, Embase, and ClinicalTrials.gov.The search period extended from the inception of the databases to February 15, 2025. Stata was used to assess publication bias, heterogeneity, and data synthesis and generate funnel plots and forest plots. The DerSimonian-Laird random-effects model was applied for the meta-analysis. The I-2 statistic was used to quantify heterogeneity and subgroup, and sensitivity analyses were conducted to explore potential sources of heterogeneity and influencing factors. Results A total of 19 randomized controlled trials with 523 participants were included. A meta-analysis revealed that hypoxic training significantly enhanced maximal oxygen uptake (VO(2)max) and maximal power output (MPO) compared to normoxic training. The standardized mean differences (SMDs) were 0.42 (95% CI: 0.16-0.67, 95% PI:-0.10, 0.94, P < 0.01, I-2 = 15.4%) forVO(2)max and 0.43 (95% CI: 0.01-0.85, 95% PI:-0.80,1.67, P < 0.05, I-2 = 56.0%) for MPO. The corresponding weighted mean differences were 191.88 mL/min forVO(2)max (95% CI: 75.66-308.10; 95% PI: 31.68-352.08; P = 0.001) and 14.53 W for MPO (95% CI: 1.40-27.66; 95% PI:-3.51-32.57; P = 0.030). Subgroup analyses revealed thatVO(2)max (SMD= 0.498, 95% CI: 0.077-0.919, P = 0.020, I2 = 0%) and MPO (SMD = 0.431, 95% CI: 0.012-0.851, P = 0.044, I-2= 0%) were significantly improved compared with the control group when the intervention duration exceeded 8 weeks. Additionally, significant improvements in VO(2)max were observed under the following conditions: fraction of inspired oxygen (FiO2) >= 15% (SMD= 0.420, 95% CI: 0.057-0.784, P = 0.024, I-2 = 12.1%), training frequency of more than three sessions per week (SMD = 0.534, 95% CI: 0.002-1.065, P = 0.049, I-2 = 0%), high-intensity protocols (SMD = 0.532, 95% CI: 0.108-0.956, P = 0.014, I-2 = 0%), session duration of less than 45 min (SMD = 0.420, 95% CI: 0.047-0.793, P = 0.027, I-2 = 0%), and high-intensity interval training (HIIT) as the intervention (SMD = 0.532, 95% CI: 0.108-0.956, P = 0.014,I-2 = 0%). Female participants showed significantly greater improvements in VO(2)max compared to the control group (SMD = 0.571, 95% CI: 0.128-1.014, P = 0.012, I-2 = 0%). Conclusions Hypoxic exercise interventions effectively improved VO(2)max and MPO in individuals with overweight or obesity, with greaterVO(2)max gains observed in women. Exercise interventions in hypoxic environments are recommended to last for longer than 8 weeks, with no more than three sessions per week of HIIT lasting less than 45 min.

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