Hypothesis

Repeated hormetic stimuli accelerate immunosenescence by chronically diverting cellular resources from antigen presentation and inflammasome regulation, unless accompanied by anti‑inflammatory nutrients that restore NAD⁺‑SIRT1 signaling.

Mechanistic Basis

Hormesis activates HIF‑1α and AMPK, suppressing mTORC1‑driven MHC II transcription and reducing SIRT1 activity via NAD⁺ consumption [1]. Chronic activation therefore lowers adaptive immune surveillance while senescent cells accumulate [3]. Anti‑inflammatory compounds such as omega‑3 fatty acids raise NAD⁺ levels and activate SIRT1, which deacetylates NF‑κB and restores inflammasome checkpoints [4]. Without this rescue, hormesis pushes the system into a maladaptive loop of inflammaging and T‑cell exhaustion [6].

Testable Predictions

1. Mice receiving intermittent cold exposure will show reduced MHC II expression on dendritic cells and increased PD‑1⁺ CD8⁺ T cells compared with controls.
2. Adding an omega‑3‑rich diet to the same hormetic regimen will normalize MHC II levels and lower PD‑1⁺ T‑cell frequency.
3. The combination group will exhibit lower senescent‑cell burden (p16^Ink4a^ positivity) and serum IL‑6 than hormesis‑only group.
4. Lifespan extension will be observed only in the combination group, not in hormesis‑only mice.

Experimental Design

• Use C57BL/6J mice, 6 months old, n=20 per group.
• Groups: (1) Control (room temp, standard diet), (2) Hormesis (4 °C 2 h/day, 5 days/week), (3) Hormesis + Omega‑3 (same cold exposure + diet supplemented with 2 % EPA/DHA), (4) Omega‑3 only.
• Duration: 12 months.
• Measure quarterly: flow cytometry for MHC II on CD11c⁺ cells, PD‑1 and CD69 on CD8⁺ T cells, serum cytokines (IL‑6, TNF‑α), senescence‑associated β‑galactosidase in liver and spleen.
• End‑point: survival analysis.

Potential Outcomes and Falsifiability

If hormesis‑only mice develop accelerated immunosenescence markers and shortened lifespan despite stress resistance, the hypothesis is supported. If omega‑3 fails to rescue MHC II expression or does not improve survival, the mechanistic link between NAD⁺‑SIRT1 signaling and hormetic immune trade‑up is falsified. Conversely, if hormesis alone improves longevity without immune detriment, the premise that hormesis inherently sacrifices immune maintenance would be rejected.

All predictions are quantitative and can be tested with standard immunological assays, making the hypothesis falsifiable.