High blood pressure results from a combination of factors, and for most people, no single cause is responsible. Genetics, diet, body weight, stress, sleep problems, and even common medications all play a role. Normal blood pressure is below 120/80 mmHg, and anything consistently at or above 130/80 is considered Stage 1 hypertension.
How Salt Raises Blood Pressure
Sodium is the single most impactful dietary factor. When you eat more salt than your body needs, your kidneys hold onto extra water to dilute it. That extra fluid increases the volume of blood flowing through your arteries, which pushes harder against artery walls.
The process goes deeper than just fluid retention. A high-sodium diet triggers your adrenal glands to release compounds that interfere with how your blood vessel walls regulate tension. These compounds cause smooth muscle cells in your arteries to tighten, raising your blood pressure even beyond what the extra fluid alone would cause. The World Health Organization recommends staying under 2,000 mg of sodium per day (just under a teaspoon of table salt), but most people consume well over that amount.
Body Weight and Belly Fat
As body weight increases, the volume of blood your heart needs to pump also increases. That alone puts more pressure on artery walls. But the location of excess fat matters as much as the amount.
Visceral fat, the deep abdominal fat surrounding your organs, is especially harmful because it behaves like an active organ. It produces hormones and inflammatory molecules that directly raise blood pressure. Visceral fat cells activate the same hormonal system your kidneys use to regulate blood pressure (the renin-angiotensin system), essentially hijacking it to push pressure higher. Large fat cells also release molecules that attract immune cells, creating a cycle of chronic low-grade inflammation that stiffens arteries and increases resistance to blood flow.
Alcohol Intake
Even moderate drinking raises blood pressure in a dose-dependent way, meaning every additional drink adds measurable pressure. A meta-analysis published by the American Heart Association found that people who consumed roughly one standard drink per day (12 grams of alcohol) had systolic blood pressure about 1.25 mmHg higher than nondrinkers. At two drinks per day, the increase was about 2.5 mmHg. At four drinks per day, systolic pressure averaged nearly 5 mmHg higher, with diastolic pressure rising about 3 mmHg.
Those numbers might sound small, but at a population level, even a 2 mmHg increase in systolic pressure meaningfully raises the risk of heart attack and stroke over time. There’s no threshold below which alcohol has zero effect on blood pressure.
Genetics and Family History
Your genes set the baseline for how your body handles sodium, how your arteries respond to stress, and how efficiently your kidneys regulate fluid. Family studies estimate that 15% to 35% of the variation in blood pressure between people comes from inherited factors. Twin studies put the number higher, around 60% for males and 30% to 40% for females.
This doesn’t mean high blood pressure is inevitable if it runs in your family. It means you may have a lower threshold for the lifestyle factors that push pressure up. Someone with a strong genetic predisposition might develop hypertension on a diet that wouldn’t affect someone else at all.
Stress and Your Nervous System
When you’re stressed, your body activates its “fight or flight” response. Your adrenal glands release adrenaline and cortisol, your heart beats faster, and your blood vessels constrict. In a short burst, this is harmless. But when stress is chronic (from work, financial pressure, caregiving, or ongoing anxiety), your nervous system stays in a heightened state. Your blood vessels spend more time constricted, your heart works harder, and over months or years, your arteries can become stiffer and less responsive.
Chronic stress also tends to drive the other causes on this list. People under sustained pressure are more likely to eat poorly, drink more alcohol, sleep less, and skip physical activity, all of which compound the direct effects of stress hormones.
Sleep Apnea
Obstructive sleep apnea, where breathing repeatedly stops and restarts during sleep, is one of the most underdiagnosed causes of high blood pressure. When your airway closes and oxygen drops, your body triggers an emergency response: your nervous system surges, blood vessels constrict, and pressure spikes. This happens dozens or even hundreds of times per night in people with moderate to severe apnea.
Over time, the repeated oxygen deprivation damages the lining of blood vessel walls, making it harder for them to relax and regulate pressure normally. If your blood pressure is high despite a healthy diet and weight, or if a partner has noticed loud snoring and pauses in your breathing, sleep apnea is worth investigating.
Medications and Supplements That Raise Pressure
Several common over-the-counter and prescription drugs can raise blood pressure, sometimes significantly. If you’re already managing hypertension, these are worth knowing about:
- Pain relievers (NSAIDs): Ibuprofen (Advil) and naproxen (Aleve) cause your body to retain sodium and fluid, which raises pressure. Occasional use is generally fine, but daily use over weeks can push numbers up noticeably.
- Decongestants: Pseudoephedrine and phenylephrine, found in many cold and sinus products, work by constricting blood vessels in your nose. They constrict blood vessels everywhere else too.
- Hormonal birth control: Birth control pills and hormonal devices raise blood pressure in some people, though the effect varies widely.
- Stimulants: ADHD medications and high-dose caffeine both activate the sympathetic nervous system. Energy drinks are a common and often overlooked source.
- Some antidepressants: Certain classes of antidepressants can raise blood pressure as a side effect.
- Herbal supplements: Licorice root, ginseng, ephedra, and guarana all have documented effects on blood pressure.
Recreational drugs including cocaine, methamphetamine, and ecstasy cause sharp, dangerous spikes in blood pressure and can trigger hypertensive emergencies even in otherwise healthy people.
Kidney and Hormone Conditions
About 5% to 10% of high blood pressure cases are “secondary hypertension,” meaning another medical condition is driving the problem. When that condition is treated, blood pressure often improves or resolves. The most common culprits involve the kidneys or hormone-producing glands.
Kidney disease, from diabetes-related damage, cysts (polycystic kidney disease), or inflamed filtering units, impairs the kidneys’ ability to remove sodium and regulate fluid balance. Narrowed arteries leading to the kidneys, often caused by the same plaque buildup that clogs coronary arteries, can also force pressure up.
On the hormonal side, overproduction of aldosterone by the adrenal glands causes the kidneys to hold onto salt and water. Thyroid disorders, both overactive and underactive, can raise blood pressure. Overactive parathyroid glands raise calcium levels in the blood, which in turn pushes pressure higher. Cushing syndrome, where the body produces too much cortisol, and rare adrenal tumors that release bursts of adrenaline, are less common but well-established causes.
Blood Pressure Categories
The 2025 guidelines from the American Heart Association and American College of Cardiology define four categories:
- Normal: Below 120/80 mmHg
- Elevated: 120 to 129 systolic, with diastolic still below 80
- Stage 1 hypertension: 130 to 139 systolic, or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic, or 90 or higher diastolic
If your systolic and diastolic numbers fall into different categories, the higher category applies. A reading of 138/76, for example, counts as Stage 1 hypertension even though the diastolic number is normal. A single high reading doesn’t mean you have hypertension. The diagnosis is based on consistently elevated readings across multiple visits or confirmed with home monitoring over time.