High Blood Pressure

High blood pressure, also called hypertension, affects over 1.3 billion people worldwide and is a major contributor to heart disease, stroke, kidney disease, and premature death. Blood pressure measures the force of blood pushing against artery walls as the heart pumps—it's expressed as two numbers: systolic (pressure when the heart beats) over diastolic (pressure between beats). Normal blood pressure is below 120/80 mmHg, while hypertension is generally defined as 140/90 mmHg or higher, though target thresholds vary by age and health status. In about 90-95% of cases, the exact cause isn't known—this is called primary or essential hypertension, resulting from complex interactions between genetics, aging, lifestyle factors, and multiple body systems. The remaining cases have identifiable causes like kidney disease, hormone disorders, or certain medications (secondary hypertension). Over time, elevated pressure damages artery walls, making them stiffer and narrower, which forces the heart to work harder and further elevates pressure—a self-perpetuating cycle. Multiple mechanisms contribute: the kidneys' regulation of salt and water balance, the renin-angiotensin-aldosterone hormonal system controlling blood vessel constriction, the sympathetic nervous system's stress response, inflammation, oxidative stress, and blood vessel dysfunction. High blood pressure typically causes no symptoms until it's caused serious damage, earning it the nickname "the silent killer"—most people only discover it through screening.

Treatment begins with lifestyle modifications that can significantly lower blood pressure: reducing salt intake, maintaining healthy weight, regular physical activity, limiting alcohol, eating more fruits and vegetables (particularly the DASH diet), managing stress, and ensuring adequate sleep. These changes alone can normalize blood pressure in mild cases. When medication is needed, multiple drug classes are available and often used in combination. ACE inhibitors and ARBs (angiotensin receptor blockers) relax blood vessels by blocking hormones that cause constriction, and also protect the kidneys and heart. Calcium channel blockers prevent calcium from entering heart and blood vessel cells, causing relaxation. Diuretics (water pills) help kidneys eliminate excess salt and water, reducing blood volume. Beta-blockers slow heart rate and reduce the force of contractions. Additional classes including alpha-blockers, direct renin inhibitors, and centrally-acting agents are available for specific situations. Most people need 2-3 medications from different classes to reach target blood pressure. Treatment is typically lifelong, though significant weight loss or sustained lifestyle changes sometimes allow medication reduction. Single-pill combinations simplifying dosing from multiple pills to one improve medication adherence. Home blood pressure monitoring helps track control and detect "white coat hypertension" (elevated readings only in medical settings) or masked hypertension (normal in clinic but elevated at home). When properly treated, most people with hypertension can achieve good blood pressure control and substantially reduce their cardiovascular risk.

Despite effective medications, blood pressure control rates remain suboptimal globally—fewer than half of people with hypertension achieve target blood pressure levels. Medication side effects including dizziness, fatigue, cough (with ACE inhibitors), ankle swelling (with calcium blockers), frequent urination (with diuretics), and sexual dysfunction contribute to poor adherence. Taking multiple pills daily for a condition causing no symptoms is challenging, and many people stop medications or take them inconsistently. Resistant hypertension—elevated blood pressure despite taking three or more medications including a diuretic at optimal doses—affects 10-15% of treated patients and lacks clear treatment pathways beyond adding more medications. Some people experience excessive blood pressure drops when standing (orthostatic hypotension), particularly with multiple medications, causing dizziness and fall risk. Cost and access barriers prevent many people worldwide from obtaining medications consistently. Better ways to predict which medications will work best for individual patients would reduce the trial-and-error approach currently needed. Young people with hypertension face decades of medication with cumulative side effects and costs, yet delaying treatment allows silent organ damage to accumulate. Salt sensitivity varies considerably between individuals, but easily identifying who benefits most from sodium restriction remains difficult. Blood pressure variability—fluctuations over time even when average levels seem controlled—independently predicts cardiovascular risk but current treatments don't specifically address it.

Several RNA-based therapies that silence genes involved in blood pressure regulation are in Phase 2 and Phase 3 trials, including drugs targeting angiotensinogen (the precursor to angiotensin) and other components of the renin-angiotensin system. These medications, given by injection every few months, could provide sustained blood pressure reduction without daily pills. Novel mineralocorticoid receptor antagonists with improved potassium safety profiles compared to current drugs like spironolactone are advancing through trials—these drugs block aldosterone's effects on salt retention and blood vessel stiffness. Dual angiotensin receptor-neprilysin inhibitors (ARNIs), already approved for heart failure, are being evaluated for hypertension, combining blood vessel relaxation with protection of beneficial peptides that lower blood pressure. New combination pills containing complementary medications in single tablets are being tested to simplify regimens and improve adherence. Endothelin receptor antagonists blocking a powerful vessel-constricting molecule are in trials after earlier safety concerns were addressed. Device-based therapies including next-generation renal denervation systems (using catheters to disrupt kidney nerves that contribute to hypertension) are in large trials following mixed earlier results—newer technology and refined patient selection may improve outcomes. Baroreflex activation therapy using implanted devices to stimulate pressure sensors in blood vessels is being evaluated for resistant hypertension. Extended-release formulations of existing drugs allowing once-weekly or even once-monthly dosing are in development to address adherence challenges.

Gene therapy approaches delivering instructions to permanently modify blood pressure-regulating systems through one-time treatments are in early development, potentially offering lifelong blood pressure control. CRISPR gene editing is being explored to disable or modify genes contributing to hypertension, though technical and ethical considerations require careful evaluation. Scientists are developing personalized medicine approaches using genetic testing, machine learning, and comprehensive phenotyping to predict which medications will work best for individual patients before starting treatment. Researchers are investigating the gut microbiome's role in blood pressure regulation, with evidence that certain bacteria produce compounds affecting the renin-angiotensin system and vessel function—interventions to modify intestinal bacteria for blood pressure control are being explored. Novel drug targets are being identified through large-scale genetic studies and proteomics, including pathways involving immune system activation, inflammation, oxidative stress, and endothelial dysfunction. Scientists are developing nanosensors and implantable monitors that continuously track blood pressure and could enable closed-loop systems automatically adjusting medication delivery in response to real-time measurements. Vaccines targeting components of the renin-angiotensin system are being investigated as potential long-lasting alternatives to daily medication. Researchers are exploring whether circadian medicine—timing medication to body clock rhythms—could improve blood pressure control with lower doses. Scientists are studying vascular aging mechanisms including cellular senescence (where cells stop dividing but remain alive and harmful) and developing drugs to reverse age-related arterial stiffening. Artificial intelligence is being applied to predict who will develop hypertension years before blood pressure rises, analyzing genetic data, imaging, lifestyle patterns, and physiological markers to enable early prevention. Novel minimally invasive procedures to alter blood vessel properties or create alternative blood flow pathways are in early research. Bioelectronic medicine approaches using targeted electrical stimulation of specific nerves to lower blood pressure are being explored as non-pharmaceutical alternatives.