Key result
, no causal verbs).
Why the study?
Aging and biological sex modulate systemic vascular dynamics and autonomic nervous system regulation, but their interaction with intracranial pulse waveform morphology during isometric stress remains poorly characterized.
How do age and sex impact intracranial pulse waveform morphology and heart rate variability during isometric stress?
Observational (n=320)
How do age and sex impact intracranial pulse waveform morphology and heart rate variability during isometric stress?
Aging is associated with significant autonomic inertia and diminished intracranial reserve during stress, establishing the P2/P1 ratio as a potential non-invasive biomarker of age-associated neurophysiological dysregulation.
Answers are grounded in this paper and cite their sources.
Elevated P2/P1 ratios and attenuated HRV in older adults suggest cerebrovascular vulnerability under stress; leaves open targeted interventions for age-related autonomic decline.
Systemic vascular dynamics and autonomic nervous system (ANS) regulation are pivotal for maintaining cerebral homeostatic stability; however, the aging process and biological sex significantly modulate these neural feedback loops. This study investigated the neurobiological interaction between cardiac autonomic modulation and intracranial pulse waveform morphology (P2/P1 ratio) during isometric stress across distinct age and sex cohorts. We evaluated 320 individuals (184 women; 136 men), stratified into young (n = 151) and older adults (n = 169) groups. Heart rate variability (HRV) and intracranial pulse waveform morphology (P2/P1 ratio), monitored via non-invasive strain-gauge technology, were assessed at baseline, during a 1-min isometric handgrip challenge, and during a 5-min post-stress recovery, with data analyzed using a three-way ANOVA. Older adults exhibited significantly altered intracranial pulse waveform morphology (elevated P2/P1 ratio) and attenuated HRV compared to younger subjects, independent of sex. Importantly, we identified a phenomenon of “sympathovagal lag” in older adults, characterized by persistent sympathetic dominance (0V pattern) following stress cessation, contrasting with the rapid homeostatic recovery observed in younger individuals. Regarding sex, older women demonstrated the most compromised intracranial compensatory status despite maintaining higher parasympathetic tone. Aging is linked to significant autonomic inertia and diminished intracranial reserve; the prolonged post-stress sympathetic response in older age suggests a window of vulnerable cerebrovascular regulation, and our results establish the P2/P1 ratio as a reliable, non-invasive biomarker of age-associated neurophysiological dysregulation.
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Oliveira et al. (2026) reported an observational. Isometric handgrip challenge vs. Younger adults was evaluated on Heart rate variability and intracranial pulse waveform morphology (P2/P1 ratio). Older adults exhibited significantly elevated intracranial P2/P1 ratio, attenuated heart rate variability, and prolonged post-stress sympathetic dominance compared to younger individuals.
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