Drinking about 16 ounces of water is one of the fastest ways to raise blood pressure, with effects starting within five minutes and peaking around 30 to 35 minutes later. In healthy older adults, that amount of water raised systolic blood pressure by about 11 mmHg in a study published in Circulation. But water is just one option. Depending on whether you need a quick fix for dizziness or a long-term strategy for chronic low blood pressure, several approaches can help.
Drink More Water, More Often
Water raises blood pressure by increasing blood volume and triggering a reflex in your nervous system that tightens blood vessels. The effect is dose-dependent: 16 ounces produces a stronger response than 8 ounces. In people with autonomic disorders (conditions where the nervous system struggles to regulate blood pressure), the same 16 ounces raised systolic pressure by 43 mmHg. Even if your situation is less dramatic, staying well-hydrated throughout the day is the simplest baseline strategy for keeping pressure from dropping too low.
Increase Your Salt Intake
Salt helps your body retain water, which expands blood volume and raises pressure. For people with orthostatic hypotension (blood pressure that drops when you stand), medical guidelines recommend significantly more sodium than the general population typically consumes. The American Society of Hypertension suggests 2,400 to 4,000 mg of sodium daily for these patients, while the Heart Rhythm Society recommends 4,000 to 4,800 mg daily for people with POTS, a condition that causes lightheadedness on standing.
A practical way to add sodium is 1,000 to 2,000 mg with each meal, through salted foods, broth, or electrolyte drinks. This is the opposite of the advice given to people with high blood pressure, so it only applies if your readings are genuinely low. Your doctor can check your sodium levels through a urine test to determine whether you need more.
Use Physical Counterpressure Maneuvers
When you feel lightheaded or sense your blood pressure dropping, certain body positions can push blood back toward your heart and brain within seconds. The American Heart Association recommends these specific techniques:
- Leg crossing with muscle tensing: Cross your legs and squeeze your thigh, buttock, and abdominal muscles. This works while standing or lying down.
- Squatting: Lower yourself into a squat, which compresses the large veins in your legs and forces blood upward. Tense your lower body and abdomen while squatting, then stand slowly once symptoms pass.
- Isometric hand grip: Hook your fingers together and pull your arms in opposite directions as hard as you can, or clench your fists at maximum force.
These maneuvers are especially useful for preventing fainting episodes. They work by temporarily increasing the resistance in your blood vessels and pushing pooled blood out of your legs.
Caffeine for a Short-Term Boost
A cup of coffee can raise blood pressure by up to 10 mmHg. The effect kicks in within about 30 minutes and peaks around an hour after drinking it. This makes caffeine a useful tool before situations where you know your blood pressure tends to drop, like standing for long periods or after meals. The boost is temporary, though, and regular caffeine drinkers may develop some tolerance to the effect.
Prevent Blood Pressure Drops After Meals
Eating diverts blood flow to your digestive system, which can cause a noticeable pressure drop, especially in older adults. This is called postprandial hypotension, and a few adjustments can minimize it.
Drinking 12 to 18 ounces of water about 15 minutes before eating helps blunt the drop. Eating six or seven smaller meals instead of three large ones reduces the amount of blood your gut demands at any one time. The type of food matters too: white bread, white rice, potatoes, and sugary drinks move quickly from your stomach to your small intestine, which accelerates the pressure drop. Swapping these for whole grains, beans, protein, and healthy fats slows digestion and keeps pressure more stable. Sitting or lying down for an hour after eating also helps.
Wear Compression Garments
Compression stockings prevent blood from pooling in your legs, which is one of the main reasons blood pressure drops when you stand. For people with orthostatic conditions, dysautonomia specialists recommend waist-high stockings rated at 20 to 30 mmHg or 30 to 40 mmHg of pressure. Knee-high stockings are easier to put on but less effective because a significant amount of blood pools in the thighs and abdomen. The tighter the garment and the more body it covers, the better it works.
Check for Nutrient Deficiencies
Low vitamin B12 levels have been linked to recurrent fainting episodes. In a case-control study published in the European Heart Journal, people who experienced three or more fainting spells had significantly lower B12 levels than those with fewer episodes, even after adjusting for age and sex. B12 deficiency can also cause anemia, which reduces the oxygen-carrying capacity of your blood and contributes to low pressure. If you eat little meat or dairy, are over 60, or take acid-reducing medications, a B12 check is worth requesting.
Prescription Medications
When lifestyle changes aren’t enough, two medications are commonly prescribed for chronic low blood pressure. The first works by tightening blood vessels, raising both standing and resting pressure. It has a short duration of about three hours, so it’s typically taken two or three times a day. The second is a type of steroid that helps your kidneys retain sodium and water, expanding your blood volume. It’s taken once daily. Both require monitoring because they can overshoot and cause high blood pressure while lying down, a common trade-off in treating chronic hypotension.
When Low Blood Pressure Becomes Dangerous
A systolic drop of just 20 mmHg can cause dizziness or fainting. For example, going from 110 to 90 mmHg is enough to make you feel unsteady. Most of the time, low blood pressure is manageable and not immediately dangerous. But certain symptoms signal a medical emergency: confusion (particularly in older adults), cold and clammy skin, pale skin color, rapid shallow breathing, or a weak and rapid pulse. These are signs of shock, which means your organs aren’t getting enough blood flow. Large, sudden drops in pressure from severe bleeding, serious infections, or allergic reactions can be life-threatening and require emergency care.