Key result
Obesity in young men is linked to exaggerated blood pressure and cardiac output during exercise.
Why the study?
Cardiovascular responses to exercise are enhanced in individuals with obesity, but the mechanisms underlying these altered responses during dynamic exercise are not clear.
Are cardiovascular responses mediated by the muscle metaboreflex augmented in obese young men during static and dynamic exercise?
Cross-Sectional (n=20)
No
Are cardiovascular responses mediated by the muscle metaboreflex augmented in obese young men during static and dynamic exercise?
Standardized Mean Difference: 2.63
p-value: p=<0.05
Augmented blood pressure and cardiac output responses to dynamic exercise in obese young men are not driven by the muscle metaboreflex, suggesting other mechanisms such as the mechanoreflex may be involved.
Exaggerated exercise hemodynamics in obese young men should not yet alter clinical practice; leaves open non-metaboreflex mechanisms for prospective study.
Studies found that cardiovascular responses to exercise are enhanced in individuals with obesity and are associated with a greater cardiac output (CO) response compared to normal weight controls. However, the mechanisms underlying these altered responses during dynamic exercise are not clear. We investigated whether the cardiovascular responses mediated by the muscle metaboreflex (MMR) activation are augmented in obese men during both static and dynamic exercise. Twenty males (10 obese (OG) and 10 non-obese (NOG)) were studied. Changes in CO, mean arterial pressure (MAP), and total vascular conductance (TVC) were compared between the two groups during dynamic handgrip exercise (DHE), post-exercise muscular ischemia (PEMI), and dynamic exercise corresponding to 40%, 60% and 80% workloads. Subjects completed 2 min of DHE at 30% of MVC, followed by 2 min of PEMI. MAP, CO, and TVC responses to DHE and dynamic exercise were significantly higher in OG, whereas there were no differences during PEMI. Increases in CO and MAP during mild to heavy dynamic exercise were seen in both groups, but the changes in these variables were greater in the OG. There were no significant differences in TVC between the two groups. Compared to NOG, the augmented blood pressure response to DHE and dynamic exercise in OG was associated with a greater increase in CO. Thus, the augmented CO and MAP responses were not associated with the activation of the MMR. Consequently, additional factors specific to obesity, such as the mechanoreflex, may have been involved.
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Lee et al. (2020) conducted a cross-sectional in Obesity (n=20). Obesity vs. Non-obese (BMI < 25 kg/m2) was evaluated on Increase in cardiac output (CO) during 80% VO2peak workload (ES 2.63, p=<0.05). Obese young men demonstrated significantly exaggerated mean arterial pressure and cardiac output responses during dynamic exercise compared to non-obese controls, which were not driven by muscle metaboreflex activation.
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