{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T08:31:04Z","timestamp":1768206664936,"version":"3.49.0"},"reference-count":87,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T00:00:00Z","timestamp":1768176000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"Aging is associated with declines in cardiorespiratory fitness and endurance performance, but this association is usually confounded by age-related declines in physical activity levels. For this reason, world-class master athletes serve as exceptional models for elucidating the limits of endurance performance in old age.<\/jats:p>\n \n Purpose<\/jats:title>\n \n To examine the physiological responses to exercise and performance characteristics of an 81-year-old male runner who, in 2025, set a new world record in the 50-km race (4h47m39s, 10.5 km h\n -1<\/jats:sup>\n ) in the 80+ category.\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n Two weeks after the world record, maximal O\n 2<\/jats:sub>\n uptake (\n \n \n \n \n V<\/mml:mi>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n O\n 2max<\/jats:sub>\n ), fractional utilization of\n \n \n \n \n V<\/mml:mi>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n O\n 2max<\/jats:sub>\n (lactate threshold [LT]), maximal fat oxidation (MFO) and running economy (RE) were assessed through incremental running tests. Limiting factors to\n \n \n \n \n V<\/mml:mi>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n O\n 2peak<\/jats:sub>\n were assessed during incremental cycling exercise by gas exchange, peak cardiac output (Q\u0307\n peak<\/jats:sub>\n ), and peak fractional O\n 2<\/jats:sub>\n extraction of the vastus lateralis (VL) muscle.\n In vivo<\/jats:italic>\n VL muscle oxidative capacity and relative resistance to O\n 2<\/jats:sub>\n diffusion were estimated using near-infrared spectroscopy (NIRS) during repeated transient arterial occlusions in well-oxygenated (k\n HIGH<\/jats:sub>\n ) and low O\n 2<\/jats:sub>\n availability (k\n LOW<\/jats:sub>\n ) conditions.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n \n \n \n \n V<\/mml:mi>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n O\n 2max<\/jats:sub>\n was 52.8 mL kg\n -1<\/jats:sup>\n \u00b7min\n -1<\/jats:sup>\n , achieved at 13.2 km h\n -1<\/jats:sup>\n . LT was attained at 10.5 km h\n -1<\/jats:sup>\n . MFO was 0.55 g\u00b7min\n -1<\/jats:sup>\n occurring at 84% of\n \n \n \n \n V<\/mml:mi>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n O\n 2max<\/jats:sub>\n and RE was 237.5 mL kg\n -1<\/jats:sup>\n \u00b7km\n -1<\/jats:sup>\n . Cycling\n \n \n \n \n V<\/mml:mi>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n O\n 2peak<\/jats:sub>\n was 2.510 L min\n -1<\/jats:sup>\n (42.6 mL kg\n -1<\/jats:sup>\n \u00b7min\n -1<\/jats:sup>\n ), Q\u0307\n peak<\/jats:sub>\n was 15.3 L min\n -1<\/jats:sup>\n , and arterial-venous O\n 2<\/jats:sub>\n difference was 16.4 mL dl\n -1<\/jats:sup>\n , comparable to fractional O\n 2<\/jats:sub>\n extraction around 75% obtained by NIRS. k\n HIGH<\/jats:sub>\n was 4.67 min\n -1<\/jats:sup>\n and k\n LOW<\/jats:sub>\n was 4.59 min\n -1<\/jats:sup>\n , suggesting high oxidative and muscle O\n 2<\/jats:sub>\n diffusing capacity.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n \n The exceptional endurance performance of this master athlete was attributed to his well-preserved\n \n \n \n \n V<\/mml:mi>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n O\n 2max<\/jats:sub>\n (to our knowledge the highest recorded in octogenarians, equivalent to the 70th percentile for healthy males aged 20\u201330 years) and a high fractional utilization of\n \n \n \n \n V<\/mml:mi>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n O\n 2max<\/jats:sub>\n , together with a great ability to oxidize fats. Analyses on the limiting factors to\n \n \n \n \n V<\/mml:mi>\n \u02d9<\/mml:mo>\n <\/mml:mover>\n <\/mml:mrow>\n <\/mml:math>\n <\/jats:inline-formula>\n O\n 2max<\/jats:sub>\n suggest that his exceptional performance was mostly due to the final steps of the oxygen cascade.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.3389\/fphys.2025.1735019","type":"journal-article","created":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T05:42:13Z","timestamp":1768196533000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Exploring the physiological limits of aging: a case study of the male 50-km world record in the 80+ age category"],"prefix":"10.3389","volume":"16","author":[{"given":"A. 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