A new study published in the journal JAMA Internal Medicine found that measuring blood pressure with the arm hanging by the side or resting on the lap can lead to higher readings than measuring it with the arm resting on a table at heart level. Researchers from John Hopkins Medicine determined that the difference in readings is likely due to the increased distance between the arm and the heart in the incorrect positions. This finding reinforces existing guidelines for taking blood pressure, as the researchers estimate that 16% of U.S. adults could be falsely diagnosed with high blood pressure if the wrong arm position is used.