JMIR Publications

ABSTRACT

Background:

Heart rate (HR) monitoring by wearable devices offers a physiological, personalized and continuous method for assessing physical activity (PA) duration and intensity. However, methods to translate HR data into meaningful PA metrics are diverse and non-standardized.

Objective:

We provide an overview on how HR data are used to quantify PA behavior and estimate physiological outcomes in adult patients with cardiovascular disease (CVD).

Methods:

A systematic search was performed in PubMed, Web of Science, and CENTRAL for studies published between 2014 and 2024. Eligible studies included adults with CVD or related risk factors wearing HR monitors to estimate PA. Data were synthesized narratively.

Results:

Twenty studies were included, spanning four HR-based PA estimation methods: (1) HR zone analysis (n=14), which assessed time spent in moderate-to-vigorous zones to evaluate guideline or training adherence; (2) physiological modelling (n=4), estimating outcomes such as energy expenditure (physical activity level, PAL) or cardiorespiratory fitness (VO2max); (3) change detection (n=1), using time-series and machine learning algorithms to quantify shifts in PA behavior; and (4) a derived personalized scoring system (n=1). While each approach demonstrated clinical promise of using HR data, external validation and methodological transparency is often lacking.

Conclusions:

HR-based PA estimation holds the promise of physiologically meaningful, personalized PA monitoring in CVD care. Modelling approaches and personalized scoring systems linking PA behavior to cardiovascular outcomes may provide highly needed clinical tools for PA management in patients. Research should prioritize algorithm transparency, clinical validation and standardization.