By Mayo Clinic staff

Low blood pressure, also called hypotension, would seem to be something to strive for. However, for many people, low blood pressure can cause symptoms of dizziness and fainting. In severe cases, low blood pressure can be life-threatening.

Although blood pressure varies from person to person, a blood pressure reading of 90 millimeters of mercury (mm Hg) or less systolic blood pressure (the top number in a blood pressure reading) or 60 mm Hg or less diastolic blood pressure (the bottom number) is generally considered low blood pressure.

The causes of low blood pressure can range from dehydration to serious medical or surgical disorders. Low blood pressure is treatable, but it's important to find out what's causing your condition so that it can be properly treated.

Depending on the reason for your low blood pressure, you may be able to take certain steps to help reduce or even prevent symptoms. Some suggestions include:

Drink more water, less alcohol. Alcohol is dehydrating and can lower blood pressure, even if you drink in moderation. Water, on the other hand, combats dehydration and increases blood volume.
Follow a healthy diet. Get all the nutrients you need for good health by focusing on a variety of foods, including whole grains, fruits, vegetables, and lean chicken and fish. If your doctor suggests using more salt but you don't like a lot of salt on your food, try using natural soy sauce or adding dry soup mixes to dips and dressings.
Go slowly when changing body positions. You may be able to reduce the dizziness and lightheadedness that occur with low blood pressure on standing by taking it easy when you move from a prone to a standing position. Before getting out of bed in the morning, breathe deeply for a few minutes and then slowly sit up before standing. Sleeping with the head of your bed slightly elevated also can help fight the effects of gravity. If you begin to get symptoms while standing, cross your thighs in a scissors fashion and squeeze, or put one foot on a ledge or chair and lean as far forward as possible. These maneuvers encourage blood to flow from your legs to your heart.
Eat small, low-carb meals. To help prevent blood pressure from dropping sharply after meals, eat small portions several times a day and limit high-carbohydrate foods such as potatoes, rice, pasta and bread. Your doctor also may recommend drinking caffeinated coffee or tea with meals to temporarily raise blood pressure. But because caffeine can cause other problems, check with your doctor before drinking more caffeinated
beverages.

Low blood pressure (hypotension) can occur in anyone, though certain types of low blood pressure are more common depending on other factors including:

Age. Drops in blood pressure on standing or after eating occur primarily in adults older than 65. Orthostatic hypotension happens after standing up, while postprandial hypotension happens after eating a meal. Neurally mediated hypotension happens as a result of a miscommunication between the brain and heart. It primarily affects children and younger adults.
Medications. People who take certain medications, such as high blood pressure medications like alpha blockers, have a greater risk of low blood pressure.
Certain diseases. Parkinson's disease, diabetes and some heart conditions put you at a greater risk of developing low blood pressure