Blood pressure. Cuff around arm listening at elbow with person sitting comfortably with arm at heart level. Automatic cuffs are available with readings made two to three times in a row as ideal. High blood pressure is greater than 140/90.
With a Sphygmo. So you take a device called a sphygmomenometer and inflate the cuff while listening to the blood flow just below the cuff. When you hear no sounds at all, that's enough. Now deflate the cuff slowly until you hear a whooshing sound (a karotkoff sound); that's the top number (systolic pressure). Keep deflating until the sounds go away again; that's the bottom number (diastolic pressure).