Earlier this month, the US guidelines for high blood pressure were changed, alerting many more Americans to their potential risk for heart disease and stroke. About 45 million American are now considered prehypertensive, meaning they have a systolic blood pressure (the top number) of 120 to 139 mm Hg or a diastolic blood pressure (the bottom number) of 80 to 89 mm Hg.
A report issued by the National Heart, Lung, and Blood Institute recommends that people with prehypertension and known hypertension make lifestyle changes to lower their risk of heart disease and stroke. Catherine Champagne, PhD, professor of research at the Pennington Biomedical Research Center in Baton Rouge, Louisiana, was the site intervention director for the PREMIER clinical trial, which examined the impact of lifestyle changes on blood pressure and heart disease. In the PREMIER study, participants were divided into three groups: a group that received advice only; an "established" group, which had 26 counseling sessions over 18 months; and an "established" plus Dietary Approaches to Stop Hypertension (DASH) group, which attended the same number of counseling sessions and followed the stricter DASH diet. Both "intervention" groups recorded their physical exercise and diet, though the DASH group kept a more detailed dietary record.
Below, Dr. Champagne discusses the lifestyle changes that have been shown to lower blood pressure, and the best ways for people to successfully make those changes.
Why have the blood pressure guidelines changed to include more people?
If people can make lifestyle modifications earlier, we might have a better chance of preventing them from becoming hypertensive. In some recent scientific studies, the risk of heart disease and stroke increased once blood pressure crept over 115/75.
What lifestyle changes do you recommended to people with hypertension or prehypertension?
In our study, we promoted weight control and increased physical activity. We recommended a diet low in sodium and high in fruits and vegetables and low-fat dairy products. We also encouraged participants to limit their alcohol consumption: one drink a day for women and two for men.
We know that all of these strategies play a role in controlling blood pressure. Some people may be less successful in diet and more successful in increasing physical activity. Others might be less successful in physical activity and more successful in diet. It's very individual.
What did the PREMIER study find?
We had two active arms in our study. The DASH diet was used in one arm, and a healthy diet was used in the other. We saw slightly better data in the people in the DASH arm, where participants had stricter dietary goals and had to monitor more of their food intake to make sure that they were complying with the diet.
In our study, the DASH diet had 25 percent of calories from fat, as opposed to the 30 percent of calories from fat that is typically allowed. We encouraged participants in the DASH group to eat 8 to 12 servings of fruits and vegetables combined. And we encouraged them to eat 2 to 3 servings of low-fat to non-fat dairy products a day because of the calcium. In addition, we asked them to limit their consumption of animal products to only about two servings per day, but at a level of 2 to 3 ounces per serving as opposed to a larger serving, such as a 24-ounce steak. We also pushed whole grains, nuts, beans and legumes. These participants recorded their calories, sodium, fat, saturated fat, fruits, vegetables and dairy products.
For the non-DASH diet group, we just taught strategies for lowering fat. Obviously, some of those strategies were to decrease consumption of fats and meats and increase consumption of fruits, vegetables, and grains. These participants only self-monitored their servings of calories, sodium and fat.
Why is self-monitoring so effective?
Self-monitoring allows people to have more of an awareness of what they're eating. People don't like to do it because it takes time and effort, but the success of it is really amazing. When people keep an accounting of what they eat, they do a much better job managing their dietary intake overall.
At what point are medications for hypertension recommended?
Doctors will often prescribe medications for people with stage 1 hypertension, and this is an area where it's beneficial to try to implement lifestyle changes. Medications are recommended with stage 2 hypertension, when you're at a level of 160/100, and it's sustained for a long period of time. Usually the first order of treatment is to use diuretics. But doctors may also use a beta-blocker or a calcium-channel blocker or an ACE inhibitor, depending on what the doctor feels the person needs.
Other than a food diary, what advice do you have for people who want to make lifestyle changes?
I think the thing to remember is that people should make these changes gradually. In order for something to be a sustained lifestyle change, you really need to make sure that you can live with it. If you change everything at once then you may end up in a position where you cannot succeed because you are trying to do too much at one time.
At around age 50, I think most people are concerned about the quality of the rest of their life. This is sort of a new beginning, and people are prompted, in many instances, to evaluate their current lifestyle and make changes.
In the PREMIER study, we had a lot of highly motivated individuals in the control arm. These people only had one individual session where we gave them printed materials on how they could make changes. A lot of these people made the changes, which shows that it can be done without professional help. Professional help just makes it easier, and a lot of people need that support.
