How Do Fitness Trackers Measure Blood Pressure

how do fitness trackers measure blood pressure

It is no secret that health is wealth. With the advance of technology, we now have so many ways to monitor all aspects of our health. One of the most convenient is a fitness tracking device with multiple features- including measuring blood pressure (BP). 

But, how do fitness trackers measure blood pressure? These cute little wearable devices have multiple methods of tracking and calculating our blood pressure. Such as PPG (optical heart rate sensor), ECG, oscillator, etc. Each system works in its own way.

Want to learn more about fitness trackers measuring your blood pressure? Read along!

What Are Fitness Trackers?

Fitness trackers come with wearable blood pressure monitors to track your activities and health indicators. It’s also called an activity tracker. These devices are programmed to measure and collect data related to your fitness or wellness. 

All fitness trackers are equipped to keep track of your distance walked, run, etc. These data are then used to calculate how many calories you have burnt. They can also monitor your heartbeat and blood pressure. With the advance of technology, you can sync all these data into your phone and combine them with your calorie consumption.  

How Do Fitness Trackers Measure Blood Pressure?

There are a few systems that fitness trackers may use to measure blood pressure. PTT and oscillometric are the two most used systems. 

how fitness trackers monitor heart rates

PTT 

PTT stands for Pulse Transit Time. How much time blood takes to travel from the heart to the wrist is known as the transit time. If the blood pressure is high, the blood travels faster, hence taking less transit time. If regular, you can observe regular transit time. 

There are a few sensors that can calculate this. The two most common are: (a) ECG or electrocardiogram and (b) optical heart rate sensor (PPG).  PPG is a sensor that measures BP using a pulse oximeter and light absorption. The sensor illuminates the skin, which helps detect the density and transition of blood. 

However, as it does not use the inflating cuff method, many find it less accurate. An excellent way to measure PTT is by combining ECG and PPG, which many companies have adopted in their fitness tracking devices.

Oscillometric 

This system uses an automatic electronic sensor to measure blood pressure. The watch/fitness tracker device is programmed to tighten or inflate. As a result, blood doesn’t flow through the narrowed arteries. Then, pressure is slowly released as blood is allowed to pass. Meanwhile, the pressure sensors detect arterial pulsations as oscillation- the highest value is noted down. This value is then used to calculate the blood pressure. 

 

How Accurate Are Fitness Trackers? 

Fitness trackers give an accurate enough reading. It is important to remember that readings from fitness trackers vary depending on the situation and environment. For example, with the increase in blood pressure, the accuracy of readings starts to decrease. So, trackers may not give you accurate or exact readings during/after runs, high-intensity workouts, etc. 

You can also observe more minor changes in the pressure. For example, your BP will be slightly lower at night than at daytime. Wrist or hand movements such as using a mouse or typing on a keyboard also hamper reading accuracy. 

If you want to check the accuracy of your fitness device, make sure to wear it to your next doctor’s appointment. When the doctor checks your blood pressure with the sphygmomanometer, you can compare the number with the reading of your fitness device. Make sure to keep your hand and wrist at the heart level. To know how to get the most accurate reading, check the next segment. 

How to Get the Most Accurate BP Measurement with Fitness Trackers

Fitness trackers are not as accurate at all times. But, we can follow a few steps to get a close enough BP reading: 

  • Sit down or lie flat and relax. Let your heart rate settle.
  • Wear the fitness tracker as advised by the manufacturer (on wrist/forearm). Make sure it’s not too loose or too tight. 
  • Avoid physical activity, caffeine consumption, smoking cigarettes, etc., before taking readings.
  • If you’re sitting down, rest your hand on a flat surface with the upper arm resting at heart level.
  • To avoid misreadings, take 2-3 readings under the same environment. Compare them and take the average reading. 

Pros and Cons of Using Fitness Trackers to Measure BP

Fitness trackers are only a substitute to measure blood pressure, as measuring BP is not the only focus of fitness trackers. Let’s see the pros and cons of using fitness tracking devices to measure BP.

Pros: 

Some pros of using fitness trackers are-

Cons: 

Some cons of using fitness trackers are-

  • Not as accurate as a sphygmomanometer
  • Accuracy declines as heart rate increases (due to high-intensity exercise or stress)
  • Sensitive to movements

Bottom Line

Thanks to technology, now we can check up on our health from the comfort of our own home. Blood pressure is an excellent indicator for your heart health and overall health, and even small fitness devices can help you keep track of your BP. we hope this article has answered your question,” how do fitness trackers measure blood pressure?” 

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Frequently Asked Questions

  1. Can fitness trackers measure high blood pressure? 

Fitness trackers can measure blood pressure, but as BP increases, accuracy declines. So, even if your fitness tracking device can conclude you have high BP, it won’t give the exact or correct readings. 

  1. Can fitness trackers show blood oxygen with blood pressure?

Yes, a few fitness trackers can measure your blood oxygen (SpO2) levels. However, these readings are not entirely correct and reliable- instead, a general health indicator. Watches with blood oxygen calculating features may cost you a bit higher as well. 

  1. Can a fitness-tracking smartwatch detect heart problems? 

A smartwatch with an ECG monitor can detect irregular heartbeats. Fitness tracking devices with a good ECG monitor can check your heart rate at any time. They can detect when you have any atrial fibrillation (Afib) or heartbeat irregularity. These detections and collected data can warn you of any heart problems you may have.