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The World Health Organization (WHO)Trusted Source estimates that 1.28 billion adults worldwide aged 30–79 have high blood pressure, or hypertension.

Over time, high blood pressure can damage blood vessels and organs. It can lead to potentially life-threatening events, such as stroke, heart attack, and organ damage.

Several medications exist to manage hypertension. However, around 20% of people with the condition have resistant hypertension, which means that medications do not bring their blood pressure into the healthy range.

Resistant hypertension has links to an increased risk of organ damage and a 50%Trusted Source greater risk of adverse cardiovascular events, compared with people who have treatable hypertension.

Some preliminary evidence suggests that diet and physical activity can lower blood pressure among those with resistant hypertension. However, to date, there is a lack of high-quality studies.

In a recent study, researchers from Duke University School of Medicine in Durham, NC, conducted a randomized clinical trial called ‘Treating Resistant Hypertension Using Lifestyle Modification to Promote Health’ (TRIUMPH) to examine the link between lifestyle changes and resistant hypertension.

They investigated how a 4-month combined diet and exercise intervention delivered in a cardiac rehabilitation setting compared with a single educational session providing the same lifestyle prescription in reducing blood pressure.

“Our findings indicate that lifestyle modifications in patients with resistant hypertension […] can successfully lose weight, increase their physical activity, and as a result, lower blood pressure and potentially reduce their risk of experiencing a heart attack or stroke due to their high blood pressure,” James A. Blumenthal Ph.D. told Medical News Today.

Blumenthal is the first and senior author of the study and J.P. Gibbons Professor of Psychiatry and Behavioral Sciences at Duke University School of Medicine.

The study appears in Circulation.

Randomized trial

The researchers recruited 140 people with resistant hypertension and an average age of 63 years. Overall, 48% of patients were female, 59% were black, 31% had diabetes, and 21% had chronic kidney disease.

All participants had a body mass index (BMI) of 25 kilograms per square meter or higher at the start of the study and did not engage in regular moderate or vigorous physical activity.

Participants, on average, were taking 3.5 prescribed blood pressure-lowering medications.

The researchers randomized the participants into one of two 4-month treatment groups. The first group of 90 participants received instructions from a nutritionist about the DASH dietTrusted Source alongside caloric and sodium reductions.

The DASH diet is a flexible eating plan that reduces sugar and saturated fat intake and increases consumption of vegetables, fruits, whole grains, fish, poultry, and legumes.

Participants in the first group exercised at a cardiac rehabilitation facility three times each week for 30-45 minutes and underwent weekly group counseling sessions to support their lifestyle changes.

The second group of 50 participants received a 1-hour educational session on blood pressure management delivered by a health educator alongside a workbook outlining an individualized diet and exercise program. The workbook included information on the DASH diet, caloric restriction, and the same exercise program as those in the other group.

The researchers recorded participants’ blood pressure before, during, and after the 4-month intervention. They also kept track of participants’ diet, weight, and cardiovascular fitness. Participants were encouraged to continue taking any pre-existing hypertensive medications throughout the trial as instructed by their doctor.

After the 4-month program, the supervised group saw a 12-point drop in resting systolic blood pressure compared with 7 points in the self-guided group. Systolic blood pressure refers to the pressure the blood exerts on the artery walls as the heart beats.

The supervised group also saw their 24-hour systolic blood pressure readings drop by 7 points, while the self-guided group saw no changes in their 24-hour blood pressure readings.

Participants in the supervised group performed well on other markers, too. They lost an average of 15.3 pounds (lbs) in weight over the study period, compared with 8.5 lbs in the self-guided group. That is around 7 kilograms (kg) and 4 kg, respectively.

They also increased their oxygen uptake by 14.8%, compared with 3.4% in the control group. Increased oxygen uptake is a positive indicator for cardiorespiratory function.

“Being a randomized control trial (RCT), the study is considered high in the pyramid of scientific evidence,” José M. Ordovás, Ph.D., Director of Nutrition and Genomics at Tufts University, MA, who was not involved in the study, told MNT.

“Obviously, more significant numbers and extended length would have made the study better and answered additional questions. However, I consider this an excellent first step towards bigger and longer studies. Another beauty of the study was its simplicity, which may have facilitated its clear answer,” he added.

Psychological mechanisms

Scientists have already shown that elements of the lifestyle changes in the study, such as reduced salt intakeTrusted Source, weight lossTrusted Source, and exerciseTrusted Source, can lower blood pressure. Which of these plays the most significant part in reducing blood pressure, however, remains unclear.

“We were unable to determine which aspects of the intervention were primarily responsible for the blood-pressure-lowering effects — whether it was the improved aerobic fitness, weight loss, greater consumption of certain nutritional components of the DASH eating plan, salt restriction, or other aspects of the intervention,” said Dr. Blumenthal.

“We believe that for the lifestyle program to be maximally effective, all components of the intervention need to be provided. There is any number of potential physiologic mechanisms that could have affected our results, which we hope to examine in the future,” he added.

“Based on the results presented, things did not work through traditional [cardiovascular disease] biochemical markers (inflammation, lipids, glucose),” said Dr. Ordovás

“Obviously, it did not work through the pathways involved in response to antihypertensive drugs because they were resistant to them. The most obvious element here may be weight loss. […] It would be interesting to see if there was a correlation between blood pressure and weight changes,” he continued.

Next steps

“All patients with hypertension should be following appropriate diet and exercise recommendations, but doing this is hard,” Dr. Edo Paz told MNT, “In my experience, lifestyle changes are rarely enough to treat even simple hypertension.”

Dr. Paz, who was not involved in the study, is vice president of medical at K Health and a cardiologist at White Plains Hospital, NY, part of the Montefiore Health System.

“Overall, the results are not surprising. Cardiac rehabilitation has already been shown to be effective in preventing heart issues and death. We use it in people with certain severe cardiac conditions, like people recovering from a heart attack or people hospitalized with congestive heart failure,” he added.

“Results of the TRIUMPH study suggest that policymakers should consider resistant hypertension as a new indication for cardiac rehabilitation with appropriate coverage by governmental agencies and private insurers,” Dr. Blumenthal said to MNT.

“Importantly, we also need to determine if such lifestyle changes can be sustained — and, if not, patients may need ‘booster’ sessions to ensure that they can maintain the healthy lifestyle choices over time,” he concluded.