The habit of crossing one’s legs while measuring blood pressure can lead to inaccurate readings. This posture, Dr. Svetlana Dodonova, a cardiologist at CMD Sverdlovsky FBU health center, explained to Gazeta.Ru, can increase blood pressure by an average of 5-10 mmHg.
Clinical studies have repeatedly confirmed that measuring blood pressure with legs crossed at the knees results in falsely elevated readings. Systolic (“upper”) pressure typically rises by 5-10 mmHg, while diastolic (“lower”) pressure increases by 2-5 mmHg.
How does this happen? Firstly, crossing the legs mechanically compresses the veins in the popliteal fossa. This forces an additional volume of blood to move from the lower limbs towards the chest. The heart then has to pump this extra blood with greater effort, which is reflected in the blood pressure numbers.
A second contributing factor is that crossing the legs acts as a hidden isometric exertion on the thigh muscles. Tensed muscles send a signal to the nervous system, causing a temporary constriction of blood vessels, the doctor elaborated.
A difference of 5-10 millimeters might seem insignificant. However, in a medical context, such a discrepancy can be critical. A false positive result could lead an individual to take medications they don’t actually need, potentially causing side effects and an excessive drop in blood pressure.
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