Pulse Wave Fingerprints of Aging Persist Across Blood Pressure Levels

A new cross-sectional study of 1,163 cardiology outpatients in Taiwan suggests that a specific set of photoplethysmographic (PPG) features tracks age consistently across a wide range of systolic blood pressure levels, raising the possibility that the pulse waveform carries an age signature that is not simply a byproduct of blood pressure.

That ambiguity motivated the new analysis, published as an original research article in Frontiers in Physiology. The study, led by Chin-Nan Lin of China Medical University and Dalin Tzu Chi Hospital with colleagues at China Medical University Hospital and CardiAxis Technology, set out to answer a specific question: are age-associated PPG characteristics consistent across different measured systolic blood pressure (SBP) levels, or do they disappear once blood pressure is taken into account?

The researchers divided their 1,163 participants into two age groups — younger than 65 and 65 or older — and then stratified them across four measured SBP bands. An exploratory intersection analysis then looked for features that differed by age group in all four strata simultaneously, a demanding consistency requirement designed to filter out blood-pressure-driven artifacts.

That screen surfaced 11 candidate features. After the researchers applied false discovery rate (FDR) correction within each stratum across all the features they had tested, 10 of the 11 candidates retained statistical significance in every one of the four blood pressure bands. In other words, the age-related differences were not confined to hypertensive participants or to one narrow pressure range; they appeared across the measured SBP spectrum, including among participants with SBP at or below 120 mmHg.

What did the older adults’ waveforms look like? According to the study, they showed higher normalized waveform width indices, prolonged systolic timing, and a higher ratio of systolic to diastolic duration — changes consistent with slower, broader pulse waves. Their harmonic composition also differed: the ratio of the second to the first harmonic (H2/H1) was lower in older participants, as was the low/high frequency ratio derived from pulse rate variability (PRV). Older adults also showed greater variability in pulse wave area. Together, these features span four domains the authors highlight: waveform morphology, pulse timing, harmonic composition and PRV-derived spectral characteristics.

The stratum analysis was descriptive, but the team went further with multivariable regression, testing whether the features remained associated with age treated as a continuous variable. Even after adjustment for measured SBP, sex, body mass index, selected cardiometabolic comorbidities and antihypertensive medication use, the features stayed significantly associated with age. That statistical persistence is the study’s central claim: the PPG signature appears to be age-related in its own right, not merely a proxy for blood pressure or the other measured covariates.

The authors are careful about scope. The study was cross-sectional, meaning it captured a single moment in time and compared groups rather than following individuals as they aged, so it cannot establish that the waveform changes progress within a person. The cohort consisted of cardiology outpatients, a population whose vascular profiles may differ from the general public’s. And the researchers state explicitly that further validation remains necessary before these candidate features can be considered established markers of vascular aging.

Subject of Research: Age-associated photoplethysmographic waveform features across systolic blood pressure strata

Article Title: Age-associated photoplethysmographic features across systolic blood pressure strata: a cross-sectional study

Article References: Lin, C.-N., Lin, J.-J., Wang, C.-C., Chang, C.-P., Hung, Y.-C., Wang, L.-C., Ko, P.-Y., & Jingling, L. (2026). Age-associated photoplethysmographic features across systolic blood pressure strata: a cross-sectional study. Frontiers in Physiology, 17, Article 1992759. https://doi.org/10.3389/fphys.2026.1992759

Image Credits: AI Generated

DOI: 10.3389/fphys.2026.1992759

Keywords: photoplethysmography, aging, vascular stiffness, systolic blood pressure, pulse rate variability, harmonic analysis, waveform morphology, cross-sectional study, cardiology, PPG, Age-associated, photoplethysmographic