Aerobic Exercise for Carotid Plaque: What Trials Show

Aerobic exercise has the best evidence for improving carotid artery wall thickness

If your goal is to improve carotid atherosclerosis, prioritize aerobic work. A 2023 meta-analysis of 34 randomized controlled trials involving 2,420 participants found that both aerobic training and high-intensity interval training (HIIT) produced statistically significant reductions in carotid intima-media thickness (cIMT) compared with no-exercise controls. Programs that combined aerobic and resistance training did not produce a statistically significant reduction in cIMT.

That finding makes aerobic exercise the leading exercise mode for this specific outcome. It does not prove that lifting harms arteries, that combined training fails to improve cardiovascular health, or that a thinner carotid wall automatically prevents a heart attack. cIMT is a structural marker linked to atherosclerosis risk, not a clinical event itself. Still, among the exercise comparisons studied, aerobic training has the strongest direct evidence for cIMT regression.

There is one frustrating limitation: the published reporting available for the central analysis does not provide the pooled mean differences, 95% confidence intervals, or heterogeneity values for each exercise subgroup. We can say which results reached statistical significance, but not how many millimeters of cIMT each program changed or what that difference means for an individual's event risk.

What the meta-analysis actually compared

Gao et al.'s 2023 meta-analysis pooled randomized trials published from 2004 through 2020. It compared exercise programs with no-exercise controls and separated them into three categories:

• Aerobic training: 25 randomized trials
• HIIT: 8 randomized trials
• Combined aerobic and resistance training: 6 randomized trials

Aerobic training and HIIT each significantly reduced cIMT. Combined training did not reach statistical significance. The difference is worth taking seriously, but the combined-training subgroup was much smaller than the aerobic subgroup. Six trials can miss an effect that 25 trials would detect, especially if the programs, participants, and ultrasound methods varied.

Trial quality was reasonably encouraging but not immaculate. Twenty-eight of the 34 trials had Jadad scores of at least 4, and 91.2% described adequate randomization. Yet most studies did not clearly report allocation concealment, and blinding participants or exercise staff is difficult to impossible. Those weaknesses can influence behavior, follow-up, and outcome assessment. Thirteen studies also came from Chinese-language journals, which makes independent verification harder and raises concern about publication bias.

HIIT and steady aerobic training appear comparable

HIIT did not beat moderate-intensity continuous training for carotid outcomes. In obese adults, Shi et al. compared HIIT with moderate-intensity continuous training and found comparable effects on carotid hemodynamic measures. The participants were obese adults, not necessarily people with documented carotid atherosclerosis, so this was not a direct test of plaque regression.

A broader 2021 meta-analysis by Maturana et al. also found no meaningful superiority of high-intensity interval exercise over moderate-intensity continuous training across cardiometabolic risk factors, including vascular outcomes. Its populations included both healthy people and people with disease, which limits atherosclerosis-specific conclusions. Together with Gao et al., however, these findings support a practical point: the accumulated aerobic stimulus may matter more than whether it arrives as intervals or steady work.

Choose the format you can perform consistently and safely. HIIT can fit a shorter schedule, while continuous aerobic training may be easier to recover from and easier to perform at higher weekly volume. The current evidence does not provide an optimal weekly dose, session duration, or intervention length for cIMT regression.

Why might combined training miss the cIMT benefit?

The simplest explanation is not that dumbbells have declared war on your carotid arteries. Combined programs may devote less time to aerobic exercise than aerobic-only programs. If total training time was constrained, adding resistance work could have reduced the aerobic dose enough to weaken its effect. The meta-analysis did not directly test that explanation.

There is also a plausible physiological explanation. Kawano et al. compared resistance-trained young men with untrained controls in a cross-sectional study and found higher central arterial wall viscosity and stiffness in the resistance-trained group. Because this was an observational comparison in young men, it cannot show that resistance training caused the difference or tell us what happens in older adults with atherosclerosis.

A 2026 systematic review by Shaw et al. found that aerobic exercise consistently reduced arterial stiffness in adults, while resistance-training effects ranged from neutral to adverse depending on volume and intensity. These findings fit the hypothesis that the vascular signals produced by heavy resistance work can differ from those produced by aerobic exercise. They do not prove that those signals cancel aerobic cIMT regression within a combined program. The direct evidence for that claim remains the small, nonsignificant combined-training subgroup in Gao et al.

Resistance training still has cardiovascular value

The cIMT result should not become an excuse to abandon strength training. In a randomized controlled trial of people with elevated blood pressure or stage-1 hypertension, Banks et al. found that resistance exercise lowered blood pressure and improved endothelial function. Blood pressure and endothelial function are not the same endpoint as cIMT, so this study does not overturn Gao et al.'s result. It does show that resistance exercise can improve vascular measures that matter.

Context also appears to matter. In a 12-week randomized study of 93 older women with a mean age of 67.2 years, Fujie et al. tested resistance training, higher dietary animal-protein intake, both together, or sedentary control. The combination improved muscle health and may have offset the increase in arterial stiffness associated with resistance training. That result cannot establish a strategy for carotid plaque regression, but it weakens any blanket claim that resistance exercise is inherently bad for arteries.

Strength training also protects muscle mass, strength, and physical function—outcomes with obvious value in later life. The sensible interpretation is narrower: if cIMT regression is the priority, do not let resistance sessions replace the aerobic volume that the direct evidence supports.

How much should cIMT matter?

cIMT measures the thickness of the inner and middle layers of the carotid artery wall. It is a surrogate endpoint, not a count of strokes, heart attacks, or deaths. Evidence summarized by Aispuru-Lanche et al. links greater cIMT with more extensive coronary atherosclerosis, and cIMT progression in people with established coronary artery disease independently predicts new coronary events.

That supports cIMT as a meaningful vascular marker. It does not tell us the clinical payoff from the exercise-associated reductions in Gao et al., because the available reporting does not provide the subgroup effect sizes or a usable threshold connecting a given cIMT change to fewer events. A statistically significant ultrasound change can be biologically relevant without having a known, patient-level effect on cardiovascular outcomes.

Who should be cautious about generalizing the result?

Older adults carry much of the burden of atherosclerosis, yet their vascular response may be less uniform. A 2024 systematic review and meta-analysis by Ho et al. found unclear and heterogeneous effects of aerobic exercise on arterial stiffness in older people. Arterial stiffness and cIMT differ, but the finding warns against assuming that every older adult will respond alike.

Individual variation also appears substantial. In a one-year randomized trial in people with type 2 diabetes, Magalhães et al. reported variability in responses to different exercise intensities, including vascular-function outcomes. Diabetes control, medication use, baseline fitness, adherence, and the training dose can all change the result. Exercise is medicine only in the loose sense that it has doses, side effects, and uneven responses; it does not arrive with a universal prescription label.

The practical verdict

For adults aiming to improve carotid artery structure, make aerobic exercise the foundation. Continuous aerobic training and HIIT both have randomized-trial evidence for significant cIMT reductions versus no exercise, and neither format has shown a meaningful advantage over the other for this purpose.

Keep resistance training for strength, blood-pressure control, endothelial function, and healthy aging. Structure it so it supplements rather than displaces your aerobic work. The evidence does not yet identify the ideal aerobic dose, prove that combined training damages arteries, or quantify how much cIMT regression reduces cardiovascular events. It does support one clear priority: protect the aerobic volume first.

Medical conditions, symptoms with exertion, known cardiovascular disease, uncontrolled hypertension, and medications that affect heart rate all warrant individualized exercise advice from a qualified clinician.