Aerobic exercise, not lifting, clearly improved blood vessel function

How well the inner lining of your blood vessels works, known as endothelial function, is a window into cardiovascular health, and it is commonly measured by flow-mediated dilation, a test of how much an artery widens when blood flow increases. Exercise is widely promoted for heart health, but the specific question here is sharper: in adults carrying excess weight, does training actually improve endothelial function, and does it matter whether that training is aerobic or resistance based? This review set out to pool the randomised trial evidence and answer both questions.

The researchers systematically searched MEDLINE, Cochrane, LILACS and EMBASE plus the grey literature for randomised controlled trials in adults aged 18 or over with a body mass index of 25.0 or higher. Ten trials involving 14 exercise groups and 400 participants met the criteria. They ran random-effects analyses for the pooled estimates and used 95% prediction intervals to express uncertainty in the results. Study quality was assessed with the Cochrane risk-of-bias 2 tool, which flagged some concerns across the included trials.

Exercise training improved flow-mediated dilation compared with no-exercise controls, a clearly significant pooled effect. When split by modality, the improvement held for aerobic training but not for resistance training, which fell just short of the significance threshold at p = 0.051. Notably, the response did not differ by weight category: people classed as overweight, obese, or both showed no meaningful difference in how their flow-mediated dilation responded to training. The authors stress that the small number of included studies means the findings should be read with caution.

The result lines up with the broader view that aerobic exercise drives favourable adaptations in blood vessel function, and it extends that picture specifically to adults with overweight and obesity. The resistance training question is left genuinely open: a result at p = 0.051 is a near miss, not a demonstration of no effect, and more trials could tip it either way. With only 10 trials and 400 participants in total, plus some quality concerns, the pooled estimates are best treated as a strong hint rather than a settled answer.

If you carry extra weight and want a reason beyond calories to do cardio, this is one: aerobic training was linked with measurably better blood vessel function in pooled trial data. It is also a reason not to read too much into your weight category, since the vascular response to training looked similar whether participants were overweight or obese. None of this says lifting is useless for your arteries; the evidence simply has not yet shown a clear effect either way for resistance work.