Association of Wearable-Derived Heart Rate Variability and Resting Heart Rate with Cardiovascular Risk in Adults: A Prospective Observational Study
Cardiovascular risk assessment traditionally depends on demographic, clinical and biochemical measurements obtained during episodic healthcare encounters. Wearable sensors enable longitudinal assessment of heart rate and heart-rate variability (HRV), potentially providing complementary information regarding autonomic cardiovascular regulation. Objective: To assess the association of wearable-derived resting heart rate and HRV indices with conventional cardiovascular-risk categories among adults without previously established cardiovascular disease. Materials and Methods: This hospital-based prospective observational analytical study included 150 adults aged 30–70 years. Participants underwent conventional cardiovascular-risk assessment including history, anthropometry, blood pressure, resting 12-lead electrocardiography, glycaemic assessment and lipid profile. A validated wrist-worn wearable device was used for at least seven days, with a target monitoring duration of 14 days. Resting heart rate, night-time nadir heart rate, standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences (RMSSD) and LF/HF ratio were analysed. Participants were classified as low-, moderate- or high-cardiovascular-risk. Results: Of 150 participants, 68 were low risk, 52 moderate risk and 30 high risks. Mean resting heart rate increased from 67.3 ± 6.8 bpm in the low-risk group to 72.5 ± 7.4 bpm in the moderate-risk group and 78.1 ± 8.3 bpm in the high-risk group (p<0.001). SDNN decreased from 52.8 ± 13.4 ms to 43.6 ± 11.7 ms and 34.9 ± 10.5 ms, respectively (p<0.001), while RMSSD decreased from 45.3 ± 12.6 ms to 35.8 ± 10.3 ms and 27.4 ± 8.9 ms (p<0.001). RMSSD demonstrated the strongest correlation with cardiovascular-risk score (r=−0.49, p<0.001), followed by SDNN (r=−0.46, p<0.001). RMSSD showed an AUC of 0.78 for identifying participants in the high-risk category. Conclusion: Higher cardiovascular risk was associated with increased resting and night-time heart rate, reduced HRV and a higher LF/HF ratio. Wearable-derived HRV, particularly RMSSD, may provide useful adjunctive information for early cardiovascular-risk assessment.