Causes of High Blood Pressure (Hypertension)
High blood pressure is primarily caused by a complex interplay of genetic predisposition and environmental factors, with obesity, excess sodium intake, insufficient physical activity, and poor diet being the most significant modifiable risk factors. 1
Primary (Essential) Hypertension (90-95% of cases)
Genetic Factors
- Genetic predisposition: Hypertension is a complex polygenic disorder with more than 25 rare mutations and 120 single-nucleotide polymorphisms identified 1
- Family history: Having close relatives with hypertension significantly increases risk
- Race/ethnicity: Higher prevalence in Black individuals
- Age: Blood pressure typically increases with age
- Genetic variants: Currently account for only about 3.5% of BP variability 1
Environmental and Lifestyle Factors
Diet-Related Factors
Obesity: One of the strongest risk factors - being continuously obese or acquiring obesity is associated with a 2.7-fold increased risk of developing hypertension 1
Sodium intake: Excessive sodium consumption is directly linked to BP increases 1
- Salt sensitivity is more common in Black individuals, older adults, and those with comorbidities like CKD, diabetes, or metabolic syndrome 1
Other dietary factors:
- Insufficient potassium intake
- Insufficient calcium and magnesium intake
- Low intake of vegetables, fruits, and fiber
- Poor overall diet quality
Behavioral Factors
- Physical inactivity: Sedentary lifestyle contributes significantly to hypertension
- Alcohol consumption: Excessive intake raises blood pressure
- Smoking: Damages blood vessels and accelerates atherosclerosis
- Chronic stress: Occupational and psychosocial stressors can elevate BP 2
Secondary Hypertension (5-10% of cases)
Secondary hypertension results from identifiable underlying conditions 3:
Renal Causes
- Chronic kidney disease
- Renovascular disease (renal artery stenosis)
- Polycystic kidney disease
- Post-renal urinary tract obstruction
Endocrine Disorders
- Primary aldosteronism
- Cushing's syndrome
- Pheochromocytoma
- Thyroid disorders (hyperthyroidism)
- Hyperparathyroidism
Other Medical Conditions
- Obstructive sleep apnea: Characterized by snoring and hypersomnolence 1
- Coarctation of the aorta
Medication-Induced Hypertension
- NSAIDs
- Oral contraceptives
- Decongestants
- Stimulants
- Corticosteroids
- Immunosuppressants
- Erythropoietin
- Certain antidepressants
- Licorice (contains glycyrrhizic acid)
Pathophysiological Mechanisms
- Sympathetic nervous system overactivity: Plays a significant role in hypertension development, particularly in early stages 2
- Renin-angiotensin-aldosterone system dysregulation: Leads to vasoconstriction and sodium/water retention
- Endothelial dysfunction: Impairs vasodilation and promotes vasoconstriction
- Altered sodium handling: Affects fluid balance and vascular resistance
- Vascular remodeling: Structural changes in blood vessels increase peripheral resistance
- Gut microbiota alterations: Emerging evidence links gut microbiome changes to hypertension 1
Risk Amplification
Hypertension risk is significantly amplified when multiple factors coexist. For example, genetic predisposition combined with obesity, high sodium intake, and physical inactivity creates a much higher risk than any single factor alone 4.
Prevention Strategies
- Weight reduction to normal BMI (becoming normal weight reduces hypertension risk to levels similar to those who were never obese) 1
- DASH diet (rich in fruits, vegetables, whole grains, and low-fat dairy)
- Sodium restriction (<2300 mg/day)
- Regular physical activity (150+ minutes/week)
- Limited alcohol consumption
- Stress management
- Adequate sleep
Understanding these causes is essential for effective prevention and management of hypertension, which remains the most important modifiable risk factor for cardiovascular disease worldwide 5.