Analyzing the Validity of Physical Activity Trackers In Terms of Heart Rate and Energy Expenditure

Faculty Sponsor

Kelly Helm


Arts and Sciences


Exercise Science

Presentation Type

Poster Presentation

Symposium Date

Spring 4-29-2021


The purpose of this study was to evaluate the agreement between two popular commercially available activity trackers and a metabolic cart in terms of energy expenditure and heart rate. The activity trackers analyzed were the Apple Watch Series 3 and the Fitbit Versa. The research hypothesis stated that a difference would be found between the Apple Watch Series 3, the Fitbit Versa, and the Parvo Medics 2400 metabolic analyzer in terms of energy expenditure and heart rate.Participants (N = 5; average age: 23.6 1.7 years) completed a Bruce Protocol maximal test. Participants were connected to the ParvoMedic metabolic analyzer while wearing the Apple Watch on their left wrist and the Fitbit Versa on their right wrist. Heart rate and caloric expenditure values were obtained from each device for analysis. Two matched-pairs t-tests were performed to compare the Apple Watch and Fitbit to the metabolic cart. The Fitbit significantly underreported heart rate and energy expenditure when compared to the true value given by the metabolic cart (p = 0.003). The Apple Watch Series 3 did appear to report slightly lower than the metabolic cart, however, the value was not statistically significant (p = 0.0981). Therefore, the research hypotheses is accepted for the Fitbit, but rejected for the Apple Watch activity tracker. Future studies should aim to gather a larger sample size.

Biographical Information about Author(s)

Stephanie Sgouroudis is a senior at Valparaiso University graduating in May of 2021 with a bachelor's degree in Exercise Science and a minor in Human Biology, Stephanie was born and raised in Valparaiso and is very involved with her community. She is passionate about sports and hopes to pursue a career where she can stay involved with athletics and human performance.

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