Oak, MOak, AOak, B2025-06-182025-06-182025-06Oak M, Oak A, Oak B. High altitude marathon physiology changes. International Journal of Advances in Medicine. 2025 Jun; 12(3): 333-3392349-39252349-3933https://imsear.searo.who.int/handle/123456789/248370High-altitude marathons present unique physiological challenges due to environmental factors such as reduced oxygen availability, decreased atmospheric pressure, and extreme temperature fluctuations. These conditions impose significant stress on the human body, requiring acute and chronic physiological adaptations to maintain performance. Acute responses include increased ventilation, elevated heart rate, and enhanced oxygen delivery mechanisms, while chronic adaptations involve hematological changes such as elevated erythropoiesis, cardiovascular remodeling, and skeletal muscle adaptations. Despite these adaptations, high-altitude conditions can substantially impact athletic performance, reducing aerobic capacity and increasing the risk of hypoxia-induced fatigue. Effective training and acclimatization strategies, such as altitude training camps and pre-acclimatization protocols, are critical for optimizing performance and minimizing the risks of high-altitude illnesses, including acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE), and high-altitude cerebral edema (HACE). Furthermore, genetic predispositions, as observed in high-altitude native populations, may influence an athlete's ability to adapt to these environments. This review explores the interplay between environmental challenges, physiological adaptations, and athletic performance in high-altitude marathons. It highlights current strategies for preparation, potential medical risks, and future research opportunities in understanding the unique demands of high-altitude endurance events. Insights from this study aim to guide athletes, coaches, and medical professionals in optimizing training, performance, and safety during high-altitude marathons.High altitude marathonHypoxiaVo2 MxGeneticsTrainingJournal ArticleIndiaOAK Hospital, Dombivli, Maharashtra, IndiaOAK Hospital, Dombivli, Maharashtra, IndiaOAK Hospital, Dombivli, Maharashtra, India