Data release and baseline analysis of the largest collection of 6-minute walk tests: the My Heart Counts Cardiovascular Health Study, a fully digital smartphone platform

The six-minute walk test (6MWT) is a sub-maximal exercise test used clinically as a measure of functional capacity. With the emergence of advanced sensors, 6MWTs were commonly performed remotely via smartphones and other devices. The My Heart Counts Cardiovascular Health Study is a smartphone application that serves as a digital platform for studies of human cardiovascular health. It has been used to perform 30,475 6MWTs on 25,539 unique participants. Here, we report on the associations of demographic and clinical variables with 6MWT distance at baseline (N=4,576), validating prior associations with male gender, height, and baseline physical activity with 6MWT distance in multivariable regression analysis. We also report associations of 6MWT baseline distance with working status (+26.8m +5.2m, P<0.001) and feeling depressed (-3.78m, +0.79m, P<0.001). In a subset of participants who conducted repeat 6MWTs separated by at least 1-week but no greater than 3-months (N=2,269), we found that use of the My Heart Counts app resulted in a statistically significant increase in 6MWT distance (+21.5m +5.72m, P<0.001). Finally, we present the public data release of our 30,475 6MWTs and the launch of a webpage-based data viewer of summary-level statistics, to compare the relative health of an individual by their age, gender, and chronic disease status. Given the importance of 6MWTs in assessment of functional capacity, our publicly-available data will serve an important purpose as a healthy and disease-specific reference for investigators worldwide.