Experts: Your Smart Watch Blood Pressure Monitor Might Not Be Accurate

Updated: Jan. 19, 2024

It's wise to check your own blood pressure, but with the rise of personal tech come a few rules expert doctors say it's important to keep in mind.

Monitoring your blood pressure is a vital part, literally, of a thorough physical at your regular doctor’s appointment. Outside the healthcare setting, there are some great blood pressure cuff devices to check your values yourself—but, say some experts, it’s possible your smart watch is not one of them.

As smart watch technology evolves, some feature digital blood pressure monitors. However, a recent review by Consumer Reports stresses that these are not always accurate.

Typically, these devices use the technology available on a wrist-worn tracker, which works much differently than an upper-arm cuff monitor. Their smart device process gathers data in a different way using the optical sensor. It serves to “approximate” blood pressure instead of giving you a true reading.

Plus, some watches need to first be calibrated with a blood pressure cuff so that a reading can be established that works for your unique biology. Essentially, if you have the cuff already, it’s more accurate to use that.

Even the phone and watch blood pressure monitors paired with cuffs, including arm and wrist versions, can be hard to use correctly without proper placement and conditions. Plus, they can be inaccurate, according to Consumer Reports’ in-house tests, and they can also be prohibitively expensive, with some unreliable models pushing almost $500. “With wrist monitors, it is difficult to position them correctly for the most accurate reading,” adds Susan Booth, a Consumer Reports test engineer. The disclaimer on one of these devices reads, in part, “Proper technique is especially important when using a wrist cuff device to obtain accurate readings. The device must be correctly placed over the radial artery and held at heart level when readings are taken, with limited movement or wrist flexion.”

Still, there are benefits to monitoring your blood pressure at home, especially for those people at high risk and those that tend to have higher readings in a healthcare setting. The American Heart Association (AHA) recommends you seek out a recommended device using the website and use a cuff size that works for you. They suggest a general cuff will not work for everyone.

Here’s How Often You Should Actually Take Your Blood Pressure, According to a Cardiologist

Plus, for accurate measurements, you need to follow some very strict guidelines, says the AHA, including:

  • Be sure you haven’t exercised, eaten, smoked, or engaged in any physical activity for a half-hour before the reading.
  • Sit quietly for at least five minutes without any distractions, including your smartphone.
  • Sit with good posture in a hard-backed chair with your feet firmly on the floor.
  • Take two readings at least a minute apart for the most accurate reading.

If keeping track of your readings is recommended by your healthcare provider, speak with them to identify the blood pressure monitor that is right for your health needs.