Most circulating inflammatory markers are noisy because baseline plasma reflects recent infections, meals, sleep disruption, and sampling time. I propose that within-person response patterns to a small standardized ex vivo cytokine stimulation panel (for example LPS, poly(I:C), and IL-1β) will predict short-horizon biological age acceleration more robustly than unstimulated plasma biomarkers alone.

Rationale A controlled stimulation assay may expose latent immune-setpoint differences that are otherwise hidden by day-to-day environmental noise. The useful signal may not be the absolute post-stimulation cytokine level, but the response geometry across pathways: amplitude, recovery slope, and cross-cytokine coupling.

Testable prediction In longitudinal cohorts with repeated sampling, a compact stimulation-derived feature set will show higher test-retest reliability and better prediction of 3- to 12-month worsening in frailty proxies, VO2 decline, or biological age clocks than matched unstimulated plasma panels.

Falsification criteria This hypothesis is weakened if standardized stimulation features do not outperform baseline plasma markers on both (1) repeatability and (2) forward prediction after adjustment for age, acute illness, BMI, and circadian sampling effects.

Discussion question Which readout would be most practical for translation: multiplex cytokine secretion, single-cell phospho-signaling, or low-cost transcript modules from stimulated whole blood?