The Effect of Acute and Chronic Exercise in Hypoxia on Circulating Vascular Endothelial Growth Factor Levels: A Systematic Review and Meta-Analysis

The present meta-analysis aims to compare the effect of acute and chronic exercise in hypoxia versus normoxia on vascular endothelial growth factor (VEGF).

In April 2024, a comprehensive search was conducted in PubMed, Web of Science, and Scopus databases to find original studies. The inclusion criteria for this study included articles published in Persian and English-language journals, with human subjects, investigating the acute and chronic effect of exercise training in hypoxia against similar exercise training in normoxia and measuring serum or plasma levels of vascular endothelial growth factor. Standardized mean (SMD) and 95% confidence intervals (CIs) were calculated using the random model.

A total of 16 studies with 283 subjects and an age range between 15 and 30 years were included in the meta-analysis. The results of data analysis showed that acute exercise in hypoxia [SMD: 0.28, P = 0.06] and normoxia [SMD: 0.25, P = 0.13] did not lead to significant changes in VEGF immediately after exercise when compared to pre-exercise. However, exercise training in hypoxia condition leads to a significant increase in VEGF compared to exercise training in normoxia [SMD: 0.76, P = 0.001].

The results showed that acute exercise training in hypoxia and normoxia had no significant effects on VEGF. Chronic exercise training in hypoxia may lead to an increase in circulating VEGF values compared to exercise training in normoxia, which indicates the role of hypoxia in the beneficial effects of exercise training.