Blood pressure is the force of blood flowing against the walls of your arteries, while heart rate is the number of times your heart beats every minute. Below, Cleveland Clinic cardiologist Michael Faulx, MD, explains some key differences — and busts some common myths along the way.

1. Blood pressure and heart rate are always linked

False: It is true that blood pressure and heart rate often rise and fall together, Dr. Faulx says.

However, if your heart rate rises, that doesn’t automatically mean your blood pressure will rise — or vice versa.

2. There’s one “normal” for blood pressure and heart rate

False: There are guidelines, but what’s normal varies from person to person.

Optimal blood pressure is typically defined as 120 mm Hg systolic (the top number, which is the pressure as your heart beats) over 80 mm Hg diastolic (the bottom number, which is the pressure as your heart relaxes). For your resting heart rate, the target is between 60 and 100 beats per minute.

3. Going “low” always indicates a problem

False: What’s healthy for one person may indicate danger for another. For example, a young, fit person may have a resting heart rate in the 50s or, in some cases, even the 40s.

Low blood pressure can be a bit trickier, especially in older patients and those with heart disease. If you’re in danger from low blood pressure, your body will tell you.

4. High blood pressure or heart rate is more likely to be dangerous

True: Dr. Faulx says the physical effects of high blood pressure take their toll on your blood vessels.

5. When you measure matters

True: To measure your resting heart rate and blood pressure, pick a time when you’re feeling relaxed, Dr. Faulx advises. Randomly sampling both measures throughout the day can also help you reach an average. Don’t take your readings right after.

Which measure is more important depends on your health, too. For patients with atrial fibrillation, heart rate might be more important to watch, but many other heart diseases depend more on blood pressure. To be safe, measure both.