Blood pressure readings, is normally a routine procedure at your doctor's office.
It is a well known fact that, with age, blood pressure tends to go upward, even if you don't have high blood pressure (hypertension). That's why regular hypertension readings, at least once a year, are indicated.
When having your blood pressure taken, sit quietly with your back supported and both feet flat on the floor. Do not cross your legs or your ankles.
What you are wearing can make a difference. Wear a shirt with short sleeves, or one that has loose sleeves that may be rolled or pushed up. If your wear anything tight around your arm, that may interfere with getting an accurate reading.
Don't eat a big meal or drink a caffeinated beverage or alcohol for at least 30 minutes before your blood pressure is taken. And if you are a smoker, don't have a cigarette for at least an hour beforehand. All of these factors can temporarily elevate the readings for a period of time and accordingly - show high blood pressure!
The same holds true if you have a full bladder - make sure you empty your bladder before your appointment.
Don't rush to your appointment. Make sure you have plenty of time to get to the clinic. Avoid talking while the reading is being taken.