The Fitness Tech Report

A study published in the Journal of the American College of Cardiology recently looked at an unusually large sample of people globally to assess the efficacy of mobile apps to motivate physical activity, discourage sitting and decrease body weight.

Do mobile apps get people moving?
Lifestyle-modification applications on smartphones have increased in popularity dramatically in recent years, many of which bundle pedometer software with daily alerts and other automated feedback, plus web-based community interaction to motivate users. Until now, the vast majority of studies on their real-world effectiveness have been small and based out of the world’s wealthiest countries.

The new study looked at approximately 69,000 people across 64 countries engaged in a “mobile technology-based health program” conducted as a 100-day global event during each of three consecutive years. Of the study’s thousands of participants, 90% lived in India. The other countries were similarly low- and middle-income countries.

Participants were organized into workplace-based teams, issued pedometers and challenged to boost their daily steps and physical activity. Pedometer data was uploaded to an interactive website providing personalized tools and analysis. Still more data was collected from online questionnaires completed by participants. All participants received encouraging emails daily.

Complete baseline and post-participation data were available for 53% of participants. Though the odds of adherence to an increased level of physical activity would seem to favor the very set of people who were also motivated to complete the program, the results are nevertheless encouraging.

Among those who completed the program, walking time increased by a mean 3,500 steps daily—about 1.75 miles per day for the average person. Exercise frequency rose by a mean of 0.89 days weekly, and sitting time fell by a mean of 45 minutes daily. Mean weight loss was 1.45 kg, or 3.2 lbs.

The fairly good adherence found in this lifestyle modification study as compared to many others suggests there is a role to play for mobile apps that encourage exercise and give feedback, particularly in low- and middle-income communities and work environments.

BP app not accurate
In other fitness technology news, a smartphone app used to measure blood pressure yields "highly inaccurate" results, researchers report in JAMA Internal Medicine.

Over 80 adults had their blood pressure measured using both the Instant Blood Pressure app and standard BP-measuring protocols. With the app, BP is estimated by placing the top edge of the smartphone on the left side of your chest and placing your right index finger over the phone's camera.

The app underestimated higher BPs and overestimated lower BPs. Overall, app measurements differed from standard readings by an average of 12.4 mm Hg systolic and 10.1 mm Hg diastolic.

The researchers say that among folks using this app, nearly 80% of those with hypertension or “hypertensive” BP will be falsely reassured that their pressure is in an acceptable range. They note that the app sold over 148,000 times before it was pulled from the market in July 2015, and it remains on many smartphones. Also, many apps that deploy very similar technology are still being sold.

For now, it’s clear that you shouldn’t use any app that uses the phone itself to measure your blood pressure. For the future, certifying the accuracy of apps that purport to deliver health information to consumers seems an important next step. Inaccurate information in the best-case scenario can lead to unwarranted anxiety; in the worst case, it may cause complacency and so ultimately harm.

A word about calorie counters
The question remains, can we trust the other fitness apps that monitor various health metrics for us in increasing ways? How widespread is the inaccuracy? Some apps are better than others, but it may be too difficult to reliably parse the two. You should take all app-collected metrics with a grain of salt.

For example, the Runtastic calorie-burning counter within the otherwise pretty good Runtastic exercise app is worthless. Even though this popular app has you input your body weight when it originally profiles you to set up your fitness goals, somewhat astonishingly, it does not use this crucial information to calculate how many calories you burned at a given activity at a certain pace for a specific duration.

Always test your calorie-burning counters against the following ironclad calorie-burning formula:

kcal/hr = METs x body weight in kg x hrs performed

Consult the Compendium of Physical Activities Tracking Guide (updated 2011) at to obtain the correct MET value per one hour of exercise performed for an incredibly diverse array of activities.

After repeatedly testing the MyFitnessPal app against this formula, it has become clear that this app is reliable and does take into account a person’s body weight when determining calories burned during various activities.

Heart rate monitors
And finally, what about heart rate apps? Just like pedometers, calorie counters and other fitness tech, heart rate monitors can vary in accuracy. To see how various heart rate apps measured up in a side-by-side test, visit:

J. Am. Coll. Cardiol., 2016, April 3 e-pub,

JAMA Internal Medicine, research letter, Mar. 2016,

MHHE, Calculating Calories Burned from Physical Activity,

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