Can Wearable Devices Accurately Measure Heart Rate Variability? A Systematic Review.

Area of Science:

• Cardiovascular physiology
• Biomedical engineering
• Wearable technology

Background:

• Numerous wearable devices claim accurate, affordable heart rate variability (HRV) measurements using photoplethysmography (PPG) or electrocardiography (ECG).
• Previous studies on the agreement between pulse rate variability (PRV) and HRV from wearables are inconclusive.
• Wearable technology offers a non-invasive alternative to traditional electrocardiogram (ECG) for RR interval estimation.

Purpose of the Study:

• To systematically review the reliability and precision of wearable devices for measuring classic HRV parameters.
• To assess wearable HRV accuracy during both rest and exercise conditions.

Main Methods:

• A comprehensive literature search was conducted across MEDLINE, SCOPUS, and the internet.
• A total of 308 articles were retrieved and screened based on predefined inclusion/exclusion criteria.
• Eighteen studies met the criteria for inclusion in the systematic review.

Main Results:

• Sixteen studies utilized ECG-based HRV technology, while two used PPG-based PRV technology.
• Wearable device accuracy for HRV detection was evaluated during rest in all included studies.
• Correlation between ECG-derived HRV and wearable HRV was excellent at rest but decreased progressively with increasing exercise intensity.

Conclusions:

• Wearable devices present a potentially valuable alternative for measuring heart rate variability (HRV).
• Further rigorous studies are required, particularly in non-stationary conditions (exercise).
• Future research should focus on robust methodologies, including adequate sample sizes and appropriate data acquisition/analysis techniques.