HIIT Improved Fitness and Blood Pressure With or Without ACE Inhibitors or ARBs

A new study of adults with metabolic syndrome found that 16 weeks of supervised high-intensity interval training improved cardiorespiratory fitness and blood pressure whether participants were taking an ACE inhibitor or angiotensin receptor blocker or were not receiving those drugs.

HIIT and antihypertensive medication are often used together in people at elevated cardiovascular risk, but researchers have questioned whether blocking the renin-angiotensin system could alter the body’s adaptation to training. A study published September 12 in the Journal of Human Hypertension followed 62 previously sedentary adults with metabolic syndrome through 16 weeks of supervised HIIT.

Twenty-seven participants were chronically taking an ACE inhibitor or angiotensin receptor blocker, while 35 were not receiving pharmacological treatment for metabolic syndrome components. Both groups improved cardiorespiratory fitness, their overall metabolic-syndrome risk score, and resting blood pressure. The investigators found no statistically significant group-by-time interaction for the main outcomes.

That is encouraging evidence that commonly prescribed renin-angiotensin system drugs did not obviously blunt the training response in this sample. It is not evidence that medication can be stopped, that HIIT is appropriate for everyone, or that the medicated and unmedicated groups were biologically equivalent.

What the 16-Week HIIT Program Changed

Participants entered the study with metabolic syndrome and overweight or obesity and reported less than 150 minutes per week of moderate physical activity. The sample included 29 women and 33 men and had an average age in the early fifties.

After the supervised training period, cardiorespiratory fitness improved in both groups. VO2max rose by 3.9 ± 2.1 mL/kg/min in the medication group and 5.0 ± 3.1 mL/kg/min in the non-medicated group. The statistical analysis supported a clear improvement over time but did not show a significant difference in the magnitude of that improvement between groups.

The composite metabolic-syndrome score also improved: by 0.22 units in the medication group and 0.30 in controls. Resting mean arterial pressure fell by 4.2 ± 8.7 mmHg in participants taking ACE inhibitors or ARBs and by 6.5 ± 6.3 mmHg in controls.

Why ACE Inhibitors and ARBs Were Worth Studying

ACE inhibitors and angiotensin receptor blockers act on the renin-angiotensin-aldosterone system, an important regulator of blood pressure and vascular function. Because that system also participates in exercise-related cardiovascular responses, researchers have been interested in whether chronic inhibition changes training adaptation.

The new findings suggest those medications were compatible with meaningful improvement from supervised HIIT. Exercise blood-pressure responses improved as well: maximal mean arterial pressure and submaximal diastolic pressure showed significant changes over time without evidence of a different pattern between the two groups.

This adds useful context to Fitness Living’s recent report that exercise plus nutrition counseling improved fasting glucose in older adults with hypertension. In both cases, structured lifestyle intervention produced measurable benefits in people with established cardiovascular risk factors rather than only in young, healthy exercisers.

The Groups Were Not Randomized by Medication

The most important limitation is the study design. Participants were compared according to whether they were already chronically taking ACE inhibitors or ARBs. They were not randomly assigned to medication versus no medication.

That means the two groups could differ in ways that influence exercise adaptation beyond the drugs themselves. The researchers adjusted analyses for baseline differences, but statistical adjustment cannot remove every source of confounding. The medicated participants were also somewhat older on average, and several baseline cardiometabolic measures differed between groups.

The medication group was heterogeneous, too. Participants used different ACE inhibitors and ARBs at varying doses. The study therefore cannot tell us whether one specific drug or dose interacts differently with HIIT.

What This Means for People Who Exercise on Blood Pressure Medication

For people prescribed an ACE inhibitor or ARB, the study offers reassurance that supervised aerobic interval training can still produce substantial improvements in fitness and blood pressure. It does not support changing a medication schedule around workouts without clinical guidance.

High-intensity interval training is also not one standardized workout. The study came from a controlled, supervised research program in adults screened for exercise participation. People with hypertension, metabolic syndrome or other cardiovascular conditions may need individualized intensity targets, medication review and medical clearance before beginning vigorous interval training.

More broadly, the result reinforces an important point: fitness improvements remain achievable even when someone is already using medication to manage risk. Fitness Living has also covered research linking both cardio and resistance training with lower diabetes risk, underscoring that exercise can address multiple components of cardiometabolic health.

What the Study Did Not Show

The trial did not test whether HIIT is superior to moderate continuous exercise for people taking ACE inhibitors or ARBs. It also did not establish long-term cardiovascular event reduction, medication reduction, or safety across every form of hypertension and metabolic disease.

The participants had metabolic syndrome and were sedentary at baseline, so the findings may not translate directly to trained athletes, people without metabolic syndrome, or patients with more complex cardiovascular or renal disease.

Future randomized studies with standardized drug regimens and larger samples would be needed to determine whether subtle differences in adaptation exist between specific medications.