This is the age of technology, information, and above all else, awareness. The world is getting serious about health and everything to do with health. Markets are flooded with “healthy” products and accessories. The health products are not limited to food and perishables; they extend to devices that can constantly monitor your vitals and keep you updated with the smallest of changes that might occur. When talking about vitals, you cannot overlook the most important of them all, which is your heartbeat or your heart rate. If you are even the least bit updated with the current trends, then you probably already know about the Smart bands and the Smartwatches. There is no escaping them. So how accurate are these devices in monitoring your heart rate, or are they just another one of those fads that pass with time? Do the devices even work effectively and reliably? This guide will enumerate upon these points for you.

What Is Smart Band and a Smartwatch?

Before embarking on the accuracy of Smart bands and Smartwatches, you should first understand them and their concept.

  • Smart Band: Smart band, also known as a smart fitness band is a band that is worn on the wrist. They are connected to bracelets or even smart bracelets. Their main function is to track your movements throughout the day. Further, the devices sport a display and mostly have the following features:
    • Pedometer
    • Heart rate sensor
    • Smart bands may also have additional features like touch screen, showing the time and the option to get connected with your Smartphone, but these are in select few and not the usual norm.
  • Smartwatch: A Smartwatch is a regular watch with smart features. It comes with additional capabilities or functionalities. Apart from the traditional feature of showing time a smartwatch also:
  • Touch screen
  • Controls Smartphone to be able to read alerts and write texts or even take calls
  • Using various apps
  • Tracks your vital rates like heart rate
  • Fitness activity tracker

Both Smart bands and Smartwatches are multi-function smart devices with Smartwatch essentially being just a smart band with the added feature of showing the time.

Heart Rate and Target Heart Rate Defined

Your heart beats to pump out blood for your body to function. The heart rate is calculated as the number of times your heart beats in a minute or BPM. Sometimes the heart beats faster, and yet sometimes it beats slower. This depends on external and internal factors like exercise, stress, age, activity, and physical exertion. Target heart rates are the defining range of your heart rate when you exercise. It tells you how fast your heart should beat while exercising. It is mostly expressed in percentage form of the maximum level of safe heart rate. The range is from 50 to 85% of maximum heart rate or exertion. To do the math, the maximum rate is 220 minus your age. So for a 30-year-old, the maximum heart rate is 220 – 30 or 190 BPM. The target heart rate then is expressed with the exertion level. At 50% exertion the THR is 190 * .50 = 95 BPM. It is these calculations that the fitness device saves you from doing, providing you with an easier and convenient way of knowing, and tracking your target heart rate.

How Does the Smart Band And Smartwatch Monitor Heart Rate?

Smart fitness devices be it Smart Bands or Smartwatches use a sensor to measure the rate with which your heart is pumping. This sensor works with the help of an LED light that makes the capillary veins of your wrist carrying blood visible to this sensor. The sensor then analyses this information by gauging the blood flow and pumps regarding your heart and displays it for your benefit in the BPM format. This method of using the blood flow to measure heart rate is known as the Optical Heart Rate Monitoring (OHRM). The OHRM is, in turn, a fancy term for PPG (Photoplethysmography)

Problems Faced by the Devices in Giving Accurate Measurement

The principle behind smart device heart rate tracking is simple enough, so what is the catch? Many fitness wearable devices fail to give accurate results. The reasons for this are:

  • Movement: The catch is that for the smart device to track your heart rate accurately, it requires you to be still. Any form of activity like talking, moving, or even sweating can throw the reading of the sensor off-track, yielding inaccurate heart rate results. However, these are the very activities that you would be indulging in while wearing such a device.
  • Position: The heart rate reading also depends on the position of the device. The heart rate slows when blood flows down to the extremities of the body. This is not factored in by the smart devices which stay on the wrist and hence give a lower reading. They readings based on PPG will be much more accurate if the devices are positioned near to the heart.

Does the Smart Device Make Use of ECG And EKG?

ECG and EKC are essentially the same things. EKG is an Electro Cardiograph that is German for ECG (Electrocardiography). This machine measures the electric impulses around your heart. It is these impulses that facilitate the contraction and expansion of your heart muscles. Hence the ECG machine is a much more accurate and superior way of heart rate monitoring. Unfortunately, the smart devices do not come equipped with the ECG function and do not use the ECG method.

How to Tell If Smart Device Is Working Correctly?

Apart from the reading inaccuracy due to movements, which is something you just have to contend with, how do you tell if your wearable smart device is at least giving you reasonable results otherwise? It’s simple, really. All you have to do is monitor your pulse by keeping your finger on the inside of your wrist for 6 seconds. Multiply it by 10 to get your heart rate per minute. Then cross-check the result with that displayed by your smart device.


Wearable smart devices are it Smart Bands or Smartwatches are not accurate at measuring heart rates. They are suitable only as an accessory but not recommended for any type of critical monitoring. Other devices like a heart rate monitor watch are much more suitable and appropriate if you are looking for accuracy.