Blood pressure

Blood pressure is the force of blood pushing against the walls of the blood vessels.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 214.} It is measured in millimeters of mercury, written mmHg.^{2International Sports Sciences Association, Strength and Conditioning, p. 94.}

A reading has two numbers. The first is the systolic pressure, and the second is the diastolic pressure.^{2International Sports Sciences Association, Strength and Conditioning, p. 94.} Systolic pressure is the pressure while the heart squeezes blood out.^{3Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 34.} Diastolic pressure is the pressure while the heart relaxes and fills with blood.^{3Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 34.} So a reading of 120/80 means 120 systolic and 80 diastolic. At rest, pressure averages about 120 mmHg systolic and 80 mmHg diastolic.^{4Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 133.}

The most common method outside a clinic uses a cuff and a stethoscope.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 214.} As air leaves the cuff, the tester listens for tapping sounds. The first sound marks the systolic pressure. The point where the sounds stop marks the diastolic pressure.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 215.}

Blood pressure changes with exercise. During aerobic exercise, systolic pressure climbs as the effort rises. Diastolic pressure barely changes.^{6Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 103.} Lifting weights raises blood pressure a lot. Peaks of 320/250 mmHg have been reported in a leg press at 95% of 1RM.^{7Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 119.} Holding the breath during a hard lift, the Valsalva maneuver, also raises it.^{2International Sports Sciences Association, Strength and Conditioning, p. 94.}

In practice

• For 30 minutes before a reading, the client shouldn’t smoke or have caffeine. They should rest, seated, for at least 5 minutes first.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 214.}
• Seat the client upright with the arm supported at heart level. Use the right cuff size.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 214.}
• Take a second reading after at least 2 minutes. If the two differ by more than 5 mmHg, take a third and average all three.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 215.}
• Take more than one reading. Repeated readings are important for finding hypertension.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 214.}

Where sources differ

The books draw “normal” in different places. The NSCA personal training text calls a reading below 120/80 mmHg normal.^{8Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 564.} Higher readings fall into the hypertension categories. The NSCA strength text says normal resting pressure generally runs from 110 to 139 systolic and 60 to 89 diastolic.^{9Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 134.}