A Single Workout Reshapes Over 3,000 Proteins Across the Body, New Atlas Reveals

When a person steps off an exercise bike after a hard workout, their body is flooded with molecular signals. For decades, scientists have known that exercise protects against type 2 diabetes, cardiovascular disease, dementia and cancer, but the precise molecular choreography that turns a single bout of physical activity into long-term health benefits has remained largely hidden. Now, a team of researchers at the University of Copenhagen and collaborating institutions has produced the most detailed picture yet of how the human body communicates with itself during and after exercise, tracking thousands of proteins simultaneously across blood, saliva and urine.

The study, published in Nature Metabolism, followed 25 healthy young men who performed 45 minutes of moderate-intensity cycling at roughly 75 percent of their maximum heart rate. The researchers collected blood, saliva and urine samples before exercise and at multiple timepoints afterwards, spanning from immediately post-exercise to a full 24 hours of recovery. Using a combination of mass spectrometry for saliva and urine and the Olink Explore HT affinity-based platform for plasma, they quantified 10,128 proteins in total. Of these, 3,007 — about 30 percent — were significantly regulated by the single exercise session, each following its own fluid-specific and time-specific trajectory.

The technical design of the study was critical to its power. Frequent sampling at approximately 0, 0.5, 1, 3 and 24 hours after exercise allowed the team to resolve temporal dynamics that coarser studies would miss. To confirm that the exercise protocol produced genuine physiological effects, the researchers measured canonical metabolic and inflammatory markers. Glucose, insulin and C-peptide rose immediately after exercise and then overcorrected below baseline between half an hour and three hours later, while the cytokines IL-6 and IL-10 showed a delayed but sustained elevation before returning to baseline by three hours. These time courses reproduced the well-established acute exercise response, validating the platform before any novel discoveries were made.

Each body fluid told a strikingly different story. Plasma, the primary conduit for inter-organ communication, exhibited a dramatic spike in protein regulation immediately after exercise, with 2,156 unique proteins — 40 percent of the quantified plasma proteome — showing significant time effects, followed by rapid normalization. Saliva, by contrast, displayed sustained bidirectional changes that persisted through the entire 24-hour recovery period, affecting 601 proteins, or 31 percent of the salivary proteome. Urine showed a more modest and transient response, with 272 regulated proteins that resolved completely by 24 hours. Despite these divergent dynamics, 297 proteins were altered in at least two fluids simultaneously, and seven changed in all three, hinting at a coordinated systemic response that transcends compartmental boundaries.

The salivary findings were particularly unexpected. Saliva is rarely considered in exercise omics studies, yet the analysis revealed that exercise-responsive salivary proteins originated from salivary glands, liver, bone marrow and lymphoid tissues, reflecting both local glandular secretion and systemic endocrine signals. One cluster of proteins, elevated and sustained through 24 hours, was strongly enriched for associations with metabolic disease: 52 of 145 unique proteins in this cluster were linked to type 2 diabetes risk in the UK Biobank protein-disease atlas. Notably, 132 FDA-approved drug targets were identified in the salivary proteome, 41 of which were exercise-responsive, suggesting that acute exercise transiently modulates pathways that are chronically dysregulated in diabetes.

Urine told a complementary story about kidney function and cellular turnover. Proteins that decreased after exercise were associated with keratinization and elastic fibre formation and originated from epithelial cells, consistent with increased filtration of cellular shedding by-products. Proteins that increased were linked to signal transduction and iron uptake, with enrichment for hepatocytes and distal nephron segments. Unlike saliva, urinary exercise-responsive proteins were not enriched for classically secreted proteins, indicating they arose from cellular shedding or tubular secretion rather than active endocrine signalling. This suggests the kidneys act as a filtering window on exercise-induced tissue remodelling, sympathetic activity and altered blood flow.

To understand how these compartments coordinate, the researchers built protein-protein correlation networks across fluids. Immediately after exercise, network connectivity expanded by roughly 1.7-fold relative to pre-exercise, with vesicle-associated proteins such as CD63 and TSG101 and integrin-linked cytoskeletal regulators forming highly connected hubs. By one hour, modules shifted toward cellular stress responses and translation activation; by three hours, toward metabolic and endocrine regulation; and by 24 hours, toward immune cell mobilization, growth factor activity and tissue repair. Throughout all timepoints, extracellular matrix remodelling proteins — including collagens, SPARC and fibulin family members — remained centrally positioned, indicating that structural reorganization is a persistent backbone of the exercise response.

Replication in an independent cohort of 24 middle-aged adults, 62.5 percent of them women, performing aerobic, high-intensity interval and resistance exercise in a randomized crossover design confirmed the generality of the findings. Despite differences in age, sex and exercise modality, 1,212 proteins — 56 percent of those regulated in the discovery cohort — responded consistently, and 74 percent of all time-responsive proteins showed concordant direction of effect immediately post-exercise. Only two proteins exhibited a modality-by-time interaction, while 804 showed a main effect of modality, indicating that exercise type influences response magnitude rather than direction for most proteins. The acute stress response appears universal, while recovery trajectories become increasingly personalized with age, sex and training mode.

The team then integrated human genetics to ask which exercise-responsive proteins matter for disease. Using colocalization analysis from the Open Targets Platform, which identifies loci where protein abundance signals and disease signals arise from the same genetic variant, they constructed networks linking secreted exerkines to health traits. Cardiometabolic diseases emerged as central hub nodes, with proteins such as FGF5, FURIN and COL4A1 converging on cardiovascular outcomes and KLK13, CTSF and PAM on metabolic health. Crucially, 69 of the colocalized secreted exercise-regulated proteins are targets of FDA-approved drugs, offering tangible starting points for exercise-mimetic therapeutics for people unable to exercise — though the authors caution that no single drug can recapitulate the full systemic benefits of physical activity.

Finally, the researchers functionally validated prioritized candidates in fruit flies, using muscle-specific RNAi knockdown of Drosophila orthologues of human exerkines. The results were striking: knockdown of PDGF, TNF or FGF orthologues impaired training-induced endurance adaptation without affecting naive performance, while myostatin knockdown enhanced baseline endurance but abolished further training gains. GDF15 and BMP4 knockdown increased endurance across conditions, and several knockdowns altered sleep, feeding behaviour and whole-body lipid storage after chronic training. These experiments demonstrate that exercise-responsive human plasma proteins are not passive biomarkers but conserved, muscle-derived regulators of exercise adaptation, behaviour and metabolism. The complete atlas has been released as an open-access interactive resource, providing a foundation for precision exercise prescription, biomarker development and the rational design of therapies that activate exercise-responsive pathways.

Subject of Research: Multi-fluid proteomic responses to acute exercise and their genetic links to cardiometabolic disease

Article Title: Systemic proteomic dynamics of acute exercise reveal genetic links to health and disease

Article References: Systemic proteomic dynamics of acute exercise reveal genetic links to health and disease. (n.d.). https://doi.org/10.1038/s42255-026-01621-w

Image Credits: AI Generated

DOI: 10.1038/s42255-026-01621-w

Keywords: exercise, proteomics, exerkines, plasma, saliva, urine, metabolism, type 2 diabetes, cardiometabolic disease, GWAS colocalization, Drosophila, skeletal muscle