It’s July! Summer time! Time to vacation and unwind. Head to your favorite beach, plop down on your beach chair and watch the waves role in. You can feel yourself relaxing, calming down. You can actually feel your blood pressure (BP) dropping. Does the presence of water really lower BP? Researchers actually did this study. They found that viewing water in an outdoor setting (for example a lake) reliably lowered BP compared to looking at grass field. Aside from water watching, what else is new in the world of hypertension (high blood pressure)?
Before diving into new data, some basics about hypertension. Despite knowing about high BP for more than 100 years and despite the fact that nearly 50% of the population has hypertension, we still do not know what causes it. What is the definition of hypertension? Hypertension is diagnosed as a BP greater than 130/80 on multiple occasions over several weeks. What is the ideal BP? 115/75. Several studies have shown that treating BP to under 120 mmHg improved outcomes versus treating to a BP under 140 mmHg. The under 120 mmHg group had fewer heart events, lower mortality and less cognitive decline. It is important to understand that the BP is not one single, stable number. Rather BP goes up and down, like waves on the ocean, with activity, time of day, and medications among other factors. The goal is to have nice, calm undulating waves of BP, not tidal waves with extreme highs and very low lows. Also, the goal is to have the BP average under 140 mmHg, or more ideally, under 120 mmHg. Hypertension is treated with lifestyle modifications and medications. Lifestyle changes include exercise, weight loss, smoking cessation and following a DASH diet. Sodium reduction (a low salt diet) is also important for treatment. First line medications for hypertension fall into three classes of drugs: diuretics (hydrocholorothiazide, chlorthalidone), calcium channel blockers (amlodipine) and angiotension converting enzyme inhibitors (lisinopril, ramipril) or angiotension receptor blockers (losartan, olmesartan). Reducing BP with medications reduces the risk of dying, reduces stroke by 35-40%, reduces heart attack by 20-25%, reduces heart failure by more than 50% and decreases the risk for dementia and cognitive impairment.
Of the three classes of medications, which one is best? A recent study followed 33,000 patients for 23 years looking at the three types of medications and assessing outcomes. The researchers found no difference among the three classes in their BP lowering efficacy and no difference in cardiovascular mortality or stroke.
In this era of BP medications is a low salt diet still recommended? High sodium (salt) intake has long been associated with hypertension. BP clearly goes up with sodium intake of 2 grams per day (2 grams of sodium is about 88% of a teaspoon of table salt). It is estimated that Americans eat on average 3.4 grams of salt per day. The optimal goal for salt intake is about 1.5 grams per day. Lowering sodium intake can reduce BP by 5 to 6 mmHg. Does this effect persist if patients are already on BP meds? A recent trial studied 213 people on BP medications. They were given a high sodium diet for one week, then a low sodium diet the second week and their BPs were tracked. BP was 8 mmHg higher on the high sodium diet. The low sodium diet consistently lowered BP, on top of the presence of medication. The conclusion, “Don’t underestimate the power of salt”.
Elevated systolic BP is linked to mild cognitive impairment and dementia. Hypertension may cause dementia by direct and indirect methods. A direct mechanism is the known risk between hypertension and stroke. Multiple small strokes due to elevated BP can cause dementia over time. An indirect mechanism is atrial fibrillation. Hypertension is associated with atrial fibrillation, which in turn can cause blood clots which break off from the heart and travel to the brain. It has long been felt, but not proven, that BP lowering reduced the risk for dementia. However, new data is beginning to emerge. Now we have learned that just by taking medication, dementia can be avoided. A study from Italy followed 215,000 patients for seven years. The patients were starting BP medications for the first time. It was found that the patients who were more adherent to their BP meds (more likely to take their meds) had lower odds of going on to dementia. Another recent study was the first definitive trial to show that BP reduction lowered the risk for dementia. The study looked at 34,000 patients age 40 and older. In patients with intensive BP reduction (goal < 130/80), dementia was lowered by 15% and cognitive impairment improved as well. These results are exciting because now there is a potential tool to prevent dementia.
In order to control your blood pressure and reduce your risk for dementia this summer, don’t forget to take your medications regularly, follow a low salt diet and head out to the beach.
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