Heart and Vascular Health How to Tell If Your Blood Pressure Is Too Low By Heart and Vascular Institute, February 7, 2018 If your blood pressure is too low, you may be at risk of hypotension, or low blood pressure. So how low is too low? What Is Blood Pressure? Blood pressure is the measure of how hard your blood pushes against the walls of your arteries as it moves through your body. Your body is designed to adjust your blood pressure to make sure your organs and tissue receive enough oxygen. Blood pressure is indicated by two numbers formatted as a fraction, like 120/80. The systolic number (the top number) indicates how hard your blood pushes when your heart pumps, and the diastolic number (the bottom number) measures how hard your blood pushes between heartbeats when your heart relaxes and fills with blood. Check your heart with the help of the UPMC Heart and Vascular Institute. Normal or Too Low? Most doctors agree that a healthy blood pressure is anything under 120/80 mmHg. But how low is too low for blood pressure? Hypotension can occur when blood pressure drops below 90/60 mmHg. This isn’t a hard and fast rule, though. Since factors, like age, weight, and level of physical activity contribute to blood pressure, your doctor may not diagnose you with hypotension even if your blood pressure is a little low. Low blood pressure typically becomes an issue only if you’re experiencing symptoms, such as: Dizziness Nausea Excessive thirst Blurred vision Fatigue Confusion Rapid breathing Cold, clammy skin If you have one or more of these symptoms and suspect your blood pressure is low, talk to your doctor. Causes of Low Blood Pressure It’s important to know what causes your blood pressure to drop. Hypotension occurs when your body can’t bring your blood pressure back to normal fast enough after an event causes it to drop. Factors that lower blood pressure can vary from person to person. In some cases, being dehydrated is enough to cause a dip. For others, certain medicines can lower pressure. Other things that can affect blood pressure include: Exercise Stress Sleep Dehydration Some prescription medicines Over-the-counter cold medicines Who Is at Risk of Having Low Blood Pressure? Low blood pressure typically isn’t a problem for most adults. However, if your blood pressure drops suddenly or you experience symptoms, it may cause serious side effects. The U.S. National Library of Medicine indicates that a drop as little as 20 mmHg can cause problems. So what causes your blood pressure to drop and when does it put you at risk? Minor and temporary things can affect blood pressure, like getting up too fast after sitting, standing for long periods of time, or dehydration. Similarly, certain health conditions are risk factors for hypotension, including: Heart conditions Thyroid disease Severe infections Diabetes Parkinson’s disease Intestinal bleeding Severe burns Serious trauma Shock caused by blood loss If you experience low blood pressure, you’re at a higher risk for fainting and shock, which can require medical treatment if vital organs. Keep track of your blood pressure regularly so you get to know what’s normal for you and what may be too low. A single measurement lower than normal isn’t cause for alarm but if you experience other symptoms, talk to your doctor. For more information about low blood pressure or to find a doctor, contact the UPMC Heart and Vascular Institute.