Abstract Body (Do not enter title and authors here): Introduction:
Arterial stiffness is an important marker of cardiovascular health, but measuring it requires specialized equipment and trained personnel. This study aimed to evaluate a novel method for estimating arterial stiffness using photoplethysmography (PPG) signals recorded by a commercially available device (Oura Ring) and to study the impact of a high-intensity interval training (HIIT) intervention on arterial stiffness.
Research Questions:
1. Can a smart ring provide accurate estimates of arterial stiffness comparable to the reference device (Sphygmocor)?
2. Does a three-month supervised HIIT cycling protocol reduce arterial stiffness?
Aims:
1. Evaluate a PPG-based arterial stiffness estimation method using a smart ring.
2. Assess the efficacy of HIIT in reducing arterial stiffness and improving VO2max.
Methods:
The study comprised two parts:
1. A cross-sectional study (N=300, age 18-78) for collecting arterial stiffness data using the Sphygmocor and the Smart Ring to evaluate the PPG-based algorithm.
2. A randomized exercise intervention pilot study (N=80, a subset of the cross-sectional study), assigned to either a three-month HIIT protocol or a control group. Arterial stiffness was measured pre- and post-intervention using both devices. Pearson’s correlation coefficients assessed the agreement between the novel method and reference device, and effects of the intervention were analyzed using ANCOVA.
Results:
The novel PPG-based method demonstrated good correlation with the Sphygmocor device (R = 0.77 and 0.80 in pre- and post-timepoints, respectively). However, despite improving the participants’ aerobic fitness (average increase in VO2max of 1.41 ml/min/kg; 95% CI: [0.15, 2.67], P = 0.029) the HIIT intervention did not significantly improve arterial stiffness, as measured by both methods.
Conclusions:
The developed smart ring method provides a reliable, non-invasive, and continuous estimation of arterial stiffness. This innovative approach could significantly impact how arterial stiffness is monitored in an everyday setting. The null results of the HIIT intervention suggest that HIIT may not be effective in reducing arterial stiffness, highlighting the need for further research into different exercise modalities for cardiovascular health improvement. This study underscores the potential of wearable technology in cardiovascular health monitoring and the importance of evaluating diverse exercise protocols for arterial health.