Observation of serum erythropoietin concentrations in female athletes for up to eight days after a marathon run.

Erythropoietin (EPO) was studied in 13 female marathon runners before and up to 8 days after a competition marathon run. The median baseline control value was 13.7 U/l. No change in EPO concentration was found immediately (15 min.) and one day after the run. However, a median increase in EPO concentration (18.1 U/l) was found on day three post-exercise (p< 0.05). On day 8 no change was found compared to pre-exercise values. This late increase in EPO concentration would seem to be responsible for the well known increase of red blood cell mass in long distance runners.

Water immersion is associated with an increase in aquaporin-2 excretion in healthy volunteers.

Here, we report the alterations in renal water handling in healthy volunteers during a 6 h thermoneutral water immersion at 34 to 36 degrees C. We found that water immersion is associated with a reversible increase in total urinary AQP2 excretion.