ACC 2009: Exercise and Weight Loss Boosts BP-Lowering Effect of the DASH Diet

from <a href="" target="_blank">Heart<i>wire</i></a> &#151; a professional news service of WebMD

Fran Lowry

April 02, 2009

April 2, 2009 (Orlando, Florida) — Adding aerobic exercise and weight loss to the Dietary Approaches to Stop Hypertension (DASH) diet boosted its efficacy in lowering blood pressure in patients with high-normal or mildly elevated blood pressure, a small study shows. The comprehensive lifestyle changes also resulted in improved blood glucose levels, baroreflex sensitivity, and left ventricular mass, according to the results of the ENCORE study, which was presented here at the American College of Cardiology 2009 Scientific Sessions.

Senior author Dr Alan Hinderliter (University of North Carolina, Chapel Hill), who announced the results of the 16-week trial in a late-breaking clinical-trials session, said that the bottom-line message is that weight loss and exercise should be part of every lifestyle-modification program for patients with higher-than-optimal blood pressure.

Others, however, say the ENCORE study was too small and underpowered to warrant changing hypertension guidelines.

ENCORE Confirms What Everyone Knows

Dr Hani Sabbah (Henry Ford Health System, Detroit, MI) said that ENCORE confirms what the American Heart Association and cardiologists in general have been telling patients for years: to lose weight. "So it's not news to most of us that if you have high blood pressure and you lose weight, the blood pressure will come down," he told heartwire .

What is news, however, is the extent to which weight loss and exercise augment the cardiovascular benefits of the DASH diet, said Hinderliter.

To determine this, the ENCORE investigators, led by Dr James Blumenthal (University of North Carolina, Chapel Hill), enrolled 144 unmedicated, sedentary, overweight or obese individuals (average body mass index 33 kg/m2) with blood pressures between 130 and 160 mm Hg systolic and 85 to 100 mm Hg diastolic and randomized them to 16 weeks of one of the following treatments: DASH diet plus caloric restriction and exercise (n=49); DASH diet alone (n=46); or usual care (n=49). Exercise consisted of 30 minutes of treadmill walking three times per week.

Subjects on DASH Plus Diet and Exercise the Biggest Losers

The subjects assigned to the DASH plus caloric restriction and exercise group had the greatest drop in blood pressure and lost the most weight.

Weight Loss, Blood Pressure Reduction at 16 Weeks in ENCORE

Outcome DASH+caloric restriction and exercise (n=49) DASH alone (n=46) Usual care (n=49)
Reduction in systolic BP (mm HG) -13 -5 -1
Reduction in diastolic BP (mm Hg) -11 -9 -6
Change in weight (lbs) -19 -0.6 +1.9

Subjects in the DASH plus diet and exercise group also had more improvement in their cardiovascular disease risk profile as measured by blood glucose levels, baroreflex sensitivity, and left ventricular mass compared with the other subjects.

ENCORE Limited by Small Numbers

An important limitation of ENCORE is the small numbers--just under 50 in all three groups, noted Sabbah to heartwire . Also, he would have liked to see an effect of weight loss by itself and not weight loss combined with exercise. "Some patients with hypertension cannot exercise, so it would be useful to see the effect of caloric restriction alone, whether that would also boost the efficacy of the DASH diet."

Sabbah added that the results of ENCORE are not sufficient to change current guidelines, mainly because the study was underpowered. "Most likely any diet that encourages you to eat fruit and drink less fatty milk products and so on is going to be better for you than the alternative. This study is way too small, way too underpowered, for us to really be able to make recommendations based on the results. I would not make recommendations, and I don't think even the guideline committee would even consider making recommendations, without a larger, more powered study that looks at more patients."

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