Microsampling techniques, particularly dried blood spots (DBS), offer a minimally invasive alternative to venipuncture for biomarker profiling in endurance exercise. This study leverages NULISAseq, an ultra-sensitive proteomics platform, to analyze inflammatory responses in athletes participating in a half-marathon. A cohort of six individuals—three endurance athletes and three sedentary controls—underwent longitudinal blood collection at five timepoints: pre-run (R-7, R-1), mid-run (R), and post-run (R+1, R+7). DBS samples were processed using the NULISAseq 250-plex Inflammation Panel to quantify inflammatory biomarkers.

Principal component analysis revealed a significant inflammatory shift in athletes during the run, with a 3.9-fold greater proteomic change than controls. Enrichment analysis identified key inflammatory markers, including IL-6, TNFRSF8, and VEGFD, with individualized response patterns suggesting distinct recovery profiles. Furthermore, Inflammation Age increased transiently in athletes post-run, indicating acute immune activation. These findings demonstrate the feasibility of field-based proteomics using DBS and highlight potential biomarkers for exercise-induced stress and recovery, which underscores the potential of high-throughput proteomics in optimizing training and recovery strategies for athletes.

The authors have declared no competing interest.

No external funding was received.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

All participants consented at an informed consent briefing, and samples were collected and processed under the approval of the Institutional Review Board at Weill Cornell Medicine, under protocol 21-05023569. All study participants consented to data and sample sharing.

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All data produced in the present study are available upon reasonable request to the authors