By David Dunaief, M.D.
We in the medical community, of course, know what the optimal blood pressure levels should be with medication. Or do we? How can that be, when we have been treating hypertension (high blood pressure) for years? This is very important to know, since according to NHANES data, approximately 76 million adults over 20 in the United States have hypertension (1). Target blood pressure may depend on age and comorbidities, such as diabetes. We know that blood pressure should be less than 150/90 mmHg for everyone. From there, the data gets a bit fuzzy.
If optimal levels are unclear, then prevention of hypertension should be crucial; if you don’t have it, you don’t have to think about this conundrum. It turns out that exercise reduces the risk of this disease. No surprise there. But the level of physical activity needed to reduce the risk is intriguing. The intensity and the duration are a lot less than we had thought, though the frequency may be higher.
Another question frequently asked is, does it matter what time you take the medication? The answer may be yes. Not only for controlling blood pressure but also for preventing diabetes.
Finally, is it ever too early to start controlling high blood pressure in those who are 18 and older? No, according to a study with significant durability. Let’s look at the research.
Lower is better — maybe
A recent study has suggested that lower is better when it comes to treating hypertension with medication. In the Systolic Blood Pressure Intervention Trial (SPRINT), results showed that lower was better when it came to controlling blood pressure (2). What levels did the research suggest? It was a systolic (top number) blood pressure of less than 120 mmHg, which is very aggressive.
To achieve this, at least three blood pressure medications were used in each patient. Compared to the standard less than 140 mmHg systolic blood pressure target, there was a significant, almost 25 percent, reduction in all-cause mortality and a 30 percent reduction in cardiovascular events. There were over 9,000 patients in this randomized controlled trial, the gold standard of studies. The patients had hypertension plus one additional comorbidity (except diabetes and prior stroke) and were over age 50. Interestingly, a quarter of patients were at least 75 years of age, making this one of the few studies with a substantial number of older hypertension patients. These results are impressive, if they hold up to analysis.
What are the caveats to this study? And there are caveats. For one thing, the study was halted and the data were released early because of these positive results, but it has yet to be published or fully analyzed. The effects on the kidneys and potential slowing of cognitive decline are being evaluated. My specific concern is that patients who want to embrace lifestyle modifications that help treat hypertension will be at higher risk of becoming hypotensive (low blood pressure) if they start out below a systolic blood pressure (SBP) of 120 mmHg on at least three medications. It is most wise to wait until the data have been published in a peer-reviewed medical journal before attempting this target blood pressure.
What about the current guidelines?
The guidelines as of 2013/2014 from both the JNC 8 and the ASH/ISH may differ slightly, but they recommend loosening the target systolic blood pressure to less than 150 mmHg for patients over 60 and 80 years of age, and 140 mmHg for most everyone else (3). Isn’t medicine wonderful? It always has the potential to change with new study data.
What about younger populations with hypertension?
Even though we talk about high blood pressure affecting younger adults, we don’t see a lot of studies focused on this topic. In the CARDIA study, results show that the cumulative effects of high blood pressure from young adult age to middle age had significant negative effects on the left ventricular function (a chamber of the heart involved in pumping blood to the body and brain), increasing the risk of heart failure (4). Interestingly a high diastolic (lower number) blood pressure had the most detrimental effect on left ventricular function, though a high systolic number also had significant negative impact. This was a prospective (forward-looking) study with a very solid duration of 25 years. The patients were 18 to 30 years old at the start of the trial and completed it at a mean age of 50. The moral of the story: treat patients who have high blood pressure, regardless of age.
Don’t forget about the bottom number — diastolic blood pressure
There was a fear that lowering diastolic blood pressure (DBP) too far would have ill effects. This is called the J-curve effect, where lowering with medication is good, but too low could have negative effects. However, in a study involving 4,000 patients, there was no increased risk of dying when the diastolic blood pressure was decreased to less than 80 mmHg (5). There were two problems with this study. One, the J-curve could happen at levels below 70 mmHg, but this was not tested. And two, patients may or may not have had cardiac events without dying, which was also not an end point.
However, another study, based on the Framingham Heart Study and the offspring of that study, showed that those with isolated systolic hypertension (>140 mmHg) and DBP <70 mmHg had increased risk of recurrent cardiovascular disease events regardless of whether they were on medication or not, compared to those who had DBP between 70 and 89 mmHg (6). In other words, there was a J-curve effect when the DBP was <70 in those with systolic hypertension.
Exercise is important for blood pressure control. But how much? In a study, results showed that walking for 10 minutes three times a day was more effective than exercising 30 minutes once per day in those with prehypertension (SBP 120-139 mmHg) (7). In another study, standing, walking or cycling at a snail’s pace (1.0 mph) every hour for 10 to 20 minutes was significantly more effective at controlling blood pressure than sitting continuously for eight hours (8).
Timing is everything!
In a prospective study, results showed that those who took their blood pressure medications at night had a 57 percent decreased risk of developing diabetes as well as a better controlled blood pressure during the night (9). This was a randomized controlled trial involving 2,012 patients for almost six years. The medications used were mainly from the ACE inhibitor, ARB and beta-blocker classes.
We know controlling blood pressure is important, but to what levels with medication remains to be determined. The potential J-curve with diastolic blood pressure may add to this complication. Remember, high blood pressure can be present at any adult age. But taking medication at night seems to be beneficial. Treating with lifestyle modifications is important to avoid medications’ dilemma.
(1) Natl Health Stat Report. 2011. (2) nih.gov. (3) JAMA. 2014;311(5):507-520; J Clin Hypertens (Greenwich). 2014;16(1):14-26. (4) J Am Coll Cardiol. 2015; 65:2679-2687. (5) ESH 2015 Abstract LB02.06. (6) Hypertension. 2015;65:299-305. (7) Med Sci Sports Exerc. 2012;44(12):2270-2276. (8) Med Sci Sports Exerc. Online Aug. 17, 2015. (9) Diabetologia online Sept. 23, 2015.
Dr. David Dunaief is a speaker, author and lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com.
This article was originally published in TBR News Media. www.tbrnewsmedia.com.