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Digital Health

We at the Ashley lab are excited to explore the many ways in which advances in mobile technologies can assist people in leading healthier lifestyles and provide patients with the ability to continuously monitor their well-being. Although wearable devices that estimate energy expenditure and heart rate, such as the Apple Watch, Fitbit, or Samsung Gear are readily available, there have been few large-scale efforts to validate the accuracy of these devices. Consequently, our work begins with clinical validation of popular fitness trackers to determine their accuracy in measuring heart rate and energy expenditure under a variety of real-life conditions (sitting, walking, running, cycling, etc.) Our initial investigation in this area suggests that most wrist-worn devices adequately measure heart rate in laboratory-based activities, but poorly estimate energy expenditure (see below). However, as mobile technology is rapidly evolving, new devices are constantly being developed and require clinical validation. Therefore, we also seek to develop a generally-applicable framework ( for future unbiased validation of personal fitness trackers.

Preliminary results from our device validation research:

Preliminary Results

In a parallel effort, the Ashley lab seeks to mine the treasure trove of fitness and cardiovascular health data that can be gathered in a population through mobile phone apps. The average adult in the U.S. checks his/her phone dozens of times each day. Because of this, phone apps that target cardiovascular health are a promising tool to quickly gather large amounts of data about a population's health and fitness, and ultimately to influence people to make healthier choices. To this end, we have developed the MyHeart Counts phone app:

The MyHeart Counts app is a personalized tool that can help users measure daily activity, fitness, and cardiovascular risk. In the first iteration of the MyHeart Counts study, over 50,000 users downloaded the app. Our results, published in JAMA Cardiology in December 2016, are in line with the accepted medical wisdom that more active people are at lower risk for diabetes, heart disease, and other health problems (see below). However, there is more to the story, as we learned that certain activity patterns are associated with a healthier state than others. For example, subjects who were active throughout the day in brief intervals had lower incidence of heart disease compared to those who were active for the same total amount of time, but got all their activity in a single longer session. In the second iteration of our study, we also aim to learn about the mechanisms that are most effective in encouraging people to lead more active lifestyles. Download the MyHeart Counts app from the iTunes store and come join our research!

Group vs. Condition