How and when your blood pressure is taken can make a difference in your systolic reading by 2 to 20 points, according to the American Heart Association and other experts. If you have hypertension, the error is more likely to be at the higher end.
When visiting the doctor or checking it yourself at home, make sure these common mistakes are not made to ensure your blood pressure reading is accurate:
1. Don’t sit on an exam table or chair with no back support. That can raise your diastolic pressure. (That’s the lower number.)
2. Don’t sit with your legs dangling or crossed. That may raise your pressure. Your feet should be flat on the floor.
3. Don’t have the cuff wrapped around clothing. That can lead to a higher reading. So can a cuff that’s too tight (too small for your arm or wrapped too tightly). And a cuff that’s too loose or too large can lead to lower readings.
4. Don’t chat with the person doing the measuring. Even a casual conversation can raise your pressure.
5. Don’t have your blood pressure measured:
- after consuming caffeine, as it temporarily raises your pressure.
- within half an hour of smoking as it can increase blood pressure.
- if your bladder is full, as it can raise your pressure.
- within 30 minutes of aerobic exercise, like brisk walking or jogging, as it can lower your pressure temporarily.
6. Don’t rest your arm above or below your heart level. That can raise or lower your blood pressure. And your upper arm should be supported at heart level by the person taking your blood pressure, not by you.
Blood pressure should be measured accurately at least twice on at least two separate occasions, before a diagnosis of hypertension or prehypertension can be made.
For those who check their blood pressure at home, the American Heart Association recommends an automatic, cuff-style, bicep (upper-arm) monitor. You should be able to find one for $50 to $100. Wrist and finger monitors give less reliable readings, says the Association.