How accurate is your fitness tracker?

The rising popularity of devices that monitor your exercise routine suggests that more people are interested in maintaining their fitness than ever before. For instance, the company behind the fitness tracking bracelet Fitbit is valued at over $4.1 billion.



The greatest benefit of wearable fitness devices is it customizes your data to your needs, it recommends how much one person needs to exercise and when to do it.

The popular notion that is almost a standard in every fitness app is the "10,000 steps a day". The origin of this slogan comes from Japanese walking clubs and a widespread marketing campaign for pedometers.  The step count is considered a reliable measure of healthy adult physical activity.

Self-monitoring and setting fitness goals using devices such as Fitbit are among the two most popular ways of changing behavior towards physical activity. The apps motivate in observing step counts in real time and reviewing inactive time. All of this is done according to custom fitness goals such as taking 10,000 steps in a day.

However, the '10,000 steps' is not a magic number. Increasing the time spent on walking is healthy. But the proportion of benefits is not uniform on the climb to your fitness goals. For instance, the benefits of going from 2000 steps to 4000 steps are much more than going from 4000 steps to 6000 steps. But more time spent on body movement is better hence, taking 6000 steps is much better than 4000 steps.

With the rising popularity of activity trackers, the new challenge is to promote 10,000 steps marketing slogan. The data supporting this recommendation was extracted from pedometers that are worn around the hip. These days manufacturers produce these devices for the wrist because they are more comfortable.

The device worn around the hips is more efficient in calculating your activity. When something is worn on the extremities, it picks up extra movements. So it will probably miscount the large movements from daily life such as sweeping the floor or doing dishes as steps. There is a great possibility that wrist-worn devices might inflate your activity count. A general rule here would be that some exercise is good but more physical activity is better.

The extended periods of sedentary behavior such as sitting can be solved through step counting. For instance, many of us have those times during the day when we sit for longer periods. By continuing to calculate the steps during these periods we can reduce our sitting time. Many apps allow you to ring an alarm if you reach a threshold for the inactive time.

The problem with monitoring the idle time is that physical activity is not a one-size-fits-all solution. People with health problems such as rheumatoid arthritis or respiratory problems, the slogan for 10,000 steps is not beneficial. The professionals that have to spend time sitting down such as taxi drivers will need to increase their physical activity count by more than 10,000 steps to counter the negative impact of sitting too long.

This debate can easily turn towards the concept of 'lifestyle medicine'. So if the public can put the message out there that fitness trackers should be merged with the lifestyle choices, it would help more people. It would be better that these apps are truly customized for everyone's particular lifestyle. This way one can easily set personalized goals that truly maximize the health benefits across populations.