Lowering sodium by 1,000 mg/day reduces systolic BP by about 4 mmHg in hypertensive people.
View the study (meta-analysis) →Every additional 20 mmHg systolic doubles the risk of stroke and ischemic heart disease.
View the study (cohorts) →Chronic hypertension accumulates cerebral microvascular damage associated with vascular dementia and cognitive decline.
View the study (meta-analysis) →⏱ 4 min read
Blood pressure is the pressure that blood exerts against the artery walls each time the heart pumps, and although it may seem like a technical parameter, it is one of the most predictive biomarkers of cardiovascular mortality that exist: every additional 20 millimeters of mercury of systolic pressure doubles the risk of stroke and ischemic heart disease in middle-aged people, which makes it the most efficient therapeutic target for reducing mortality at the population level.
Blood pressure consists of two numbers that appear separated by a slash in any clinical reading: systolic (when the heart contracts and pushes blood) and diastolic (when the heart relaxes between beats); current guidelines consider optimal blood pressure to be below 120/80 mmHg, high-normal between 120-129/80-84, grade 1 hypertension between 130-139/85-89 (the stricter US criterion), and frankly hypertensive above 140/90 mmHg according to the more traditional European criterion.
The cardiovascular system has several overlapping mechanisms for keeping blood pressure within a functional range: the renin-angiotensin-aldosterone system regulates plasma volume and arteriolar vasoconstriction, the sympathetic nervous system adjusts heart rate and vascular tone second by second, the endothelium produces nitric oxide that dilates the arteries when blood flows, and the kidneys control the excretion of sodium and water that determine circulating volume in the medium term.
When one of these systems is persistently dysregulated, blood pressure rises; when the endothelium loses its ability to produce nitric oxide (something that happens with aging, diabetes, smoking, and a sedentary lifestyle), the arteries become stiff and systolic pressure rises even though the heart is not working harder; when the kidney retains more sodium than it should, plasma volume increases and that forces the heart to pump against greater resistance.
Hypertension is the number one modifiable cause of cardiovascular mortality in the world, and what makes it especially dangerous is that for years it produces no noticeable symptoms: damage accumulates silently in the arteries of the heart, brain, kidney, and retina, and the first clinical manifestation is usually a stroke, a heart attack, heart failure, or kidney failure that arrives with an irreversible vascular substrate already behind it.
People who maintain optimal blood pressure for decades have significantly lower rates of dementia, better-preserved kidney function, and more elastic arteries at age seventy; by contrast, those who have lived with untreated or poorly treated hypertension accumulate cerebral microvascular damage (cerebral small vessel disease), which is one of the most important causes of progressive cognitive decline and vascular dementia in the older population.
Reducing dietary sodium is the most studied non-pharmacological intervention: lowering intake by 1,000 milligrams daily reduces systolic pressure by about 4 mmHg in people with hypertension and about 2 mmHg in people with normal blood pressure, according to the He and MacGregor meta-analysis published in the BMJ; the effect is dose-dependent and sustained over the long term, and it is complemented very well by increasing dietary potassium (leafy greens, legumes, bananas, potatoes), which acts as a natural counterweight to sodium.
Regular aerobic exercise reduces systolic pressure by 5 to 8 mmHg in people with hypertension, an effect equivalent to that of many first-line drugs but without their adverse effects; strength training adds complementary benefits on arterial stiffness and body composition; moderate weight loss (5 to 10 percent of body weight) reduces blood pressure in proportion to the kilos lost; and getting enough sleep (at least 7 regular hours) corrects the nocturnal sympathetic activation that keeps blood pressure high in people with poor sleep.
Some supplements and foods have robust clinical evidence for lowering blood pressure, although their effect size is always smaller than that of exercise or sodium reduction: magnesium lowers systolic pressure by about 2 mmHg in meta-analyses of randomized trials; flavanols from pure cocoa (not processed chocolate) improve endothelial function and modestly lower blood pressure; plant nitrates from beetroot, spinach, and arugula increase nitric oxide availability and lower blood pressure for several hours after intake.
High-dose marine omega-3 lowers systolic pressure by about 2 to 4 mmHg, especially in untreated hypertensive people, and raw garlic or standardized extract has shown small but consistent effects; caffeinated coffee raises blood pressure acutely, but moderate chronic consumption is not associated with long-term hypertension in habitual drinkers; alcohol, by contrast, although some believe otherwise, raises blood pressure in a dose-dependent way from the first daily drink.
Information, not medical advice. Scientific evidence reflects the quality of the studies.