Timothy West, 86, is a British actor who's seen his career go up and up and up, from his first role in 1959 through last year's appearance on the BBC's "Dad's Army: The Lost Episodes."

Unfortunately, along with his career, his blood pressure (BP) has gone up and down through the years.

Around 1990, he was gobsmacked (as they say in England) to learn he had dangerously high blood pressure. Since then, he's been conscientious about keeping it under control.

West says, "The most important part of my regime is a small portable blood pressure monitor."

He’s right. A study published in the journal Hypertension reveals that half of American adults should be monitoring their BP at home. That's because 93% have higher readings when pressure is taken in the doctor’s office than when taken at home.

For others, at-home readings are indicative of prehypertension or hypertension, while in-office readings are normal. 

Here’s how to use your at-home blood pressure monitor:

• Sit quietly in a chair with both feet on the floor for five minutes. To test, rest your arm on a flat surface with your elbow around heart level. No talking.

• Have the cuff cover about 80% of your upper arm on bare skin.

• Take the blood pressure reading twice, 60 seconds apart, and average the readings. Also check both arms. Let your doctor know your results.

• A reading of 115/75 is ideal for slowing your rate of aging. Don't accept anything above 120/85. If you need to, get help to achieve an ideal blood pressure reading.