Heart Rate Variability metrics during exercise: a comparison between standard ECG and a smart t-shirt

The monitoring of heart rate variability (HRV) in sports is gaining increasing importance in recent years. Wearable technologies enabled electrocardiographic (ECG) signal acquisition during physical activity with minimal invasiveness. This work aims to compare the HRV indices derived from gold standard ECG with those obtained from a commercial sensorized ECG t-shirt during a protocol comprising aerobic physical exercise of increasing activity. HRV signals were extracted from the ECG using standard procedures and characterized in both time and frequency domains. Moreover, a time-frequency approach was applied to test its potential for continuous HRV monitoring in particular contexts of highly variant HRV signals, such as during exercise sessions. The results demonstrated the reliability of the smart t-shirt during the overall protocol and highlighted the feasibility of time-frequency methods for continuous HRV tracking during the exercise, potentially allowing for improved monitoring of personal fitness and training status.