Blood pressure depends on dozens of variables, some you can change and some you cannot. Normal blood pressure sits below 120/80 mmHg, while stage 1 hypertension starts at 130/80 and stage 2 at 140/90. Understanding which factors push those numbers up (or down) helps you make sense of your readings and figure out where you have the most leverage.
How Your Body Controls Blood Pressure
Your cardiovascular system maintains blood pressure through a constant feedback loop. When pressure drops, the kidneys release an enzyme that triggers a hormonal chain reaction, ultimately producing two key substances: one that tightens blood vessel walls and another, a steroid hormone from the adrenal glands, that tells the kidneys to hold onto sodium and water. More sodium retention means more fluid in the bloodstream, which raises pressure. When pressure climbs too high, the system is supposed to dial back. In many people with hypertension, this feedback loop becomes overactive or fails to reset properly.
At the same time, your nervous system plays a parallel role. Stress hormones like adrenaline and noradrenaline cause blood vessels to constrict and your heart to beat faster. This “fight or flight” response is temporary in healthy situations, but chronic stress, poor sleep, or certain medical conditions can keep the system stuck in overdrive, nudging blood pressure upward around the clock.
Sodium, Potassium, and Diet
Sodium is the single most discussed dietary factor in blood pressure. When you eat more sodium than your kidneys can efficiently clear, your body retains water to dilute it, expanding blood volume and raising pressure against artery walls. The average American consumes over 3,400 mg of sodium per day, well above the recommended ceiling of 2,300 mg. Most of that excess comes from processed and restaurant food rather than the salt shaker.
Potassium works as sodium’s counterbalance. It helps the kidneys excrete sodium and relaxes blood vessel walls. Increasing potassium intake through fruits, vegetables, beans, and dairy can lower blood pressure, particularly if it’s already elevated. The ratio between the two minerals matters more than either one alone: a diet high in sodium and low in potassium is one of the strongest dietary predictors of hypertension. There’s also a less obvious connection between sodium and blood vessel function. When sodium levels in the blood are high, the cells lining your arteries stiffen, reducing their ability to produce nitric oxide, a molecule that keeps vessels relaxed and flexible.
Body Weight
Carrying extra weight forces the heart to pump harder to supply a larger body with blood. A meta-analysis of 25 studies found that every kilogram of weight lost (about 2.2 pounds) corresponds to roughly a 1 mmHg drop in blood pressure. Some studies in men with hypertension found even steeper reductions, around 3 mmHg per kilogram lost. That means losing 10 pounds could shave 5 to 14 mmHg off your readings, which for some people is enough to move from stage 1 hypertension back into the elevated or normal range.
Exercise
Regular aerobic exercise, things like brisk walking, cycling, or swimming, lowers resting blood pressure by 4 to 10 mmHg systolic and 5 to 8 mmHg diastolic. Those reductions are comparable to what a single blood pressure medication achieves for many people. The effect depends on consistency: blood pressure starts creeping back up within a few weeks of becoming sedentary again. Most of the benefit comes from the exercise itself causing blood vessels to become more flexible and responsive over time, rather than from weight loss alone, though the two often work together.
Alcohol and Caffeine
Alcohol has a dose-dependent relationship with blood pressure. Light to moderate drinking has a modest effect, but heavy use (more than three drinks a day for women, four for men) raises blood pressure significantly. Even a single session of three or more drinks causes a temporary spike. Binge drinking, defined as four drinks within two hours for women or five for men, is particularly harmful because the repeated surges in pressure stress blood vessel walls over time.
Caffeine from coffee, energy drinks, soda, or supplements can raise blood pressure in the short term. The effect varies widely between individuals. Some habitual coffee drinkers develop tolerance and see little change, while others remain sensitive.
Age and Artery Stiffness
Aging is the most powerful non-modifiable factor. As you get older, the elastic fibers in your artery walls gradually break down and are replaced by collagen, a much stiffer protein. The result is arteries that no longer stretch to absorb each heartbeat. Instead, the full force of each pulse travels through rigid vessels, which raises systolic pressure (the top number) even as diastolic pressure (the bottom number) may stay the same or fall. This is why “isolated systolic hypertension” becomes increasingly common after age 60.
Pulse wave velocity, a measure of how fast the pressure wave from each heartbeat travels through the arteries, rises steadily with age. Higher pulse wave velocity and a wider gap between systolic and diastolic readings are both markers of stiffer arteries. This structural change is partly genetic and partly driven by a lifetime of other factors on this list, especially sodium intake, smoking, and high blood sugar.
Sleep Apnea
Obstructive sleep apnea is one of the most under-recognized drivers of high blood pressure. During each apnea episode, oxygen levels drop and carbon dioxide rises, triggering surges of stress hormones that constrict blood vessels and speed up the heart. Over months and years, these repeated nightly surges rewire the nervous system: stress hormone levels stay elevated even during the daytime, keeping blood pressure chronically high.
Sleep apnea also increases inflammation throughout the body and may physically worsen itself over time. Fluid that pools in the legs during the day shifts toward the head and neck when you lie down, narrowing the upper airway and making obstruction more likely. This effect is especially pronounced in people who already have hypertension, potentially creating a cycle that leads to treatment-resistant high blood pressure. Treating sleep apnea with a breathing device during sleep reduces stress hormone levels and can meaningfully lower blood pressure, particularly in severe cases.
Medications and Supplements
Several common over-the-counter and prescription drugs raise blood pressure as a side effect. Pain relievers like ibuprofen and naproxen are among the most widely used culprits. They cause the body to retain sodium and water and reduce the effectiveness of the kidney’s pressure-regulating mechanisms. Decongestants containing pseudoephedrine or phenylephrine, found in many cold and sinus products, directly constrict blood vessels.
Hormonal birth control (pills, patches, and some devices) can raise blood pressure in some users. Several classes of antidepressants have the same potential, including SSRIs, tricyclics, and MAO inhibitors. Stimulant medications used for ADHD can also push readings higher. On the supplement side, ephedra, licorice root, ginseng, and guarana all have documented effects on blood pressure. If you’re tracking unexplained increases, a medication or supplement review is a practical first step.
Stress and the Nervous System
Chronic psychological stress keeps the sympathetic nervous system activated, releasing a steady stream of hormones that tighten blood vessels and increase heart rate. Over time, this sustained activation can contribute to lasting structural changes in blood vessel walls, compounding the effect. The connection between stress and blood pressure is well established, though its magnitude varies from person to person. What makes stress particularly tricky as a factor is that it tends to worsen other items on this list: stressed people sleep less, drink more alcohol, eat more sodium-heavy convenience food, and exercise less.
Genetics and Family History
Blood pressure runs in families. If one or both of your parents developed hypertension, your risk is substantially higher. Genetic variation influences how your kidneys handle sodium, how sensitive your blood vessels are to stress hormones, and how quickly your arteries stiffen with age. None of these genetic tendencies are destiny on their own, but they set the baseline that lifestyle factors then push up or down. Someone with a strong family history of hypertension may develop high blood pressure despite doing many things right, while someone without that history may tolerate a higher-sodium diet without the same consequences.
How These Factors Interact
Blood pressure rarely rises because of a single factor in isolation. A person with mild genetic susceptibility who gains 15 pounds, eats a high-sodium diet, and develops sleep apnea may see their readings climb much faster than any one of those factors alone would predict. The good news is that this works in reverse too. Losing weight reduces the severity of sleep apnea, which lowers stress hormone levels, which makes blood vessels more responsive to exercise. Cutting sodium improves artery flexibility independently of weight loss. The factors that matter most are the ones you can stack together: maintaining a healthy weight, staying physically active, moderating sodium and alcohol, and treating sleep disorders if they’re present.