Arnold Schwarzenegger's flexed bicep was said to be 22 inches in circumference; Mike Tyson's, 18.5 inches; and Venus Williams's, 15 inches. That's a lot of muscle.

These days, because more than 70% of adults are overweight or obese, a majority of people have biceps (unflexed) that are between 13 inches and more than 17 inches in circumference.

That makes getting an accurate blood pressure reading — important for protecting your heart and brain health — difficult because the cuff that wraps around your upper arm may be too small.

A study in the American Journal of Hypertension found that 53% of men and 34% of women need a large or extra-large cuff. The large cuff accommodates biceps that are 13 to 17 inches; the extra-large works for over 17 inches (XXL is also available.). I suggest you measure both your arms to make sure your pressure is taken accurately.

At the doctor's office, don't let the staff use just any cuff. Insist that it be the right size for your arm, and ask for a check on both arms, because the readings may vary and the higher reading of the two should be the one of record.

For at-home monitoring, standard cuffs go up to around 16 inches. You may need to a larger one.