Biochemical and hematological changes following the 120-km open-water marathon swim. A Polish group has accompanied a 61-year-old swimmer on his journey over 120 km. The athlete needed 27 hours and 33 minutes for this route.The body core temperature fell from 36.7 ° C to 35.1 ° C.
Different blood levels rose partly considerably. More details about this case under https://pubmed.ncbi.nlm.nih.gov/25177192/