Microcirculation dysfunction is closely associated with the development of obesity. Exercise intervention could effectively improve the microcirculation in obese people, but the intensity of an exercise intervention schemes often lacks of individualization and precision. FATmax is a precise and individualized exercise intensity determined on the basis of individual fat oxidation rate.

To compare the effects of aerobic exercise and combined aerobic and resistance exercise at FATmax intensity on improving the microcirculation in obese college students, and to explore the mechanism of action by analyzing the changes in nitric oxide (NO) , endogenous NO synthase (eNOS) , endothelin-1 (ET-1) and endothelial growth factor (VEGF) .

In March, 2021, Sixty-six obese college students were recruited from Hubei University for Nationalities, and equally randomized into sex-matched three groups with different 10-week interventions: aerobic exercise group (performing aerobic exercise at the FATmax intensity, 4 times a week, 60 minutes each time) , combined aerobic and resistance exercise group〔performing combined aerobic and resistance exercise at FATmax intensity, 4 times a week, 60 minutes each time (40 minutes for aerobic exercise and 20 minutes for resistance exercise) 〕, and control group (maintaining their normal living habits) . Body weight, body fat percentage, BMI, microvascular reactivity, transcutaneous oxygen pressure (TcPO₂) , muscle oxygen saturation (SmO₂) , NO, eNOS, ET-1, VEGF and HOMA-IR were tested on March 18 and June 2, 2021, respectively.

The intervention modality and duration had significant interactive effects on body weight, BMI and body fat percentage of three groups (P<0.05) . In particular, the average body weight, BMI and body fat percentage decreased significantly in both aerobic exercise group and combined aerobic and resistance exercise group after the intervention (P<0.05) . What's more, the average post-intervention levels of the above-mentioned three indicators in the two groups were significantly lower than those of the control group (P<0.05) . The intervention modality and duration had significant interactive effects on microvascular reactivity, TcPO₂ and SmO₂ of three groups (P<0.05) . In particular, the average microvascular reactivity, TcPO₂ and SmO₂ increased significantly in both aerobic exercise group and combined aerobic and resistance exercise group after the intervention (P<0.05) . In addition, the average post-intervention levels of the average microvascular reactivity and TcPO₂ in the two groups were significantly higher than those of the control group (P<0.05) . The intervention modality and duration produced obvious interactive effects on NO, eNOS, VEGF and HOMA-IR of three groups (P<0.05) . In particular, the average NO, eNOS, and VEGF increased significantly and HOMA-IR decreased significantly in both aerobic exercise group and combined aerobic and resistance exercise group after the intervention (P<0.05) . Moreover, these two groups showed higher average post-intervention levels of NO and lower average post-intervention level of HOMA-IR than the control group (P<0.05) .

Both 10-week aerobic exercise and combined aerobic and resistance exercise at FATmax intensity could reduce body weight, body fat percentage, BMI and HOMA-IR in obese college students, and the latter may be more effective in improving microvascular reactivity and HOMA-IR. These two modalities of exercise improved microcirculation may be by improving the levels of NO, ET-1, VEGF and other factors.