Activity Trackers – Are they reliable & useful?


Fitness trackers and pedometers are a fashion statement these days! We have seen many people who buy it as a fashionable thing to wear, use them for a month or two and later it is lying around some corner un-used! Are fitness trackers really helpful??

The answer is both – Yes & No!

Yes, because they help in gauging the activity levels. The accuracy of this data is often highly questionable, however, they can at least tell you on a comparable basis if you have increased your activity levels or not.

No, they are not useful for a few reasons – These devices take information from sensors like the accelerometer to track movement. The secret software algorithms and calculation to capture that movements & activity and deduce the calorie burned from that is highly variant and will differ from company to company. Wear two devices of two different companies and we bet you will see different reading on both! Besides, you may not be wearing that band all the time – so how do you account for calories burned during that time from activities.? Also, not all activities are the same; there can be many activities/sports/training/lifting weights etc done for the same duration of time but can burn different calories. You may lift 10 kg 10 times, or 15 kg 10 times within the same time duration – but both are different energy (calories) spent by the body.

Accelerometer sensors are used to measure our movement. Most trackers come with a unidirectional activity tracker. However, we move across a three-dimensional space – forward and backward, left and right, and up-and-down. Make sure you are buying a modern-day accelerometer with three-axis data that can give a better approximation of activity.

Some sensors measure the skin temperature to understand the intensity of our activity levels – warmer the skin, higher the intensity of activity we are performing and hence more calories. This means, the exact same activity done for same duration in an airconditioned gym and in a non a/c room can give different readings, even though the calories burned are the same.

Some trackers that track sleep quality, measure the same by capturing movements while we are asleep. The logic applied is- higher the movement, lower sleep quality. However, this is not an effective and accurate method of capturing the sleep quality; the most accurate method of capturing sleep data is through a polysomnogram that captures brain waves and eye movements during REM & Non-REM cycle of sleep (Read )

In a nutshell, Activity trackers can definitely tell you if you are less or more active as compared to yesterday. But the data captured by them is highly highly variable and is not reliable.

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