Effects of acute exercise on plasma erythropoietin levels in trained runners

Purpose: The purpose of this study was to investigate further the influence of exercise on erythropoietin. Methods: We observed the effects of high in tensity running on plasma erythropoietin concentration in competitive dista nce runners. A repeated measures design was used to compare the responses o f intermittent high intensity (HIGH) exercise to continuous moderate intens ity (MOD) exercise and rest (REST). The HIGH treatment consisted of 60 min of exercise alternating 5 min of running at similar to 90% of (V)over dot O -2max with 5 min of brisk walking. The MOD treatment consisted of a continu ous 60-min run on the treadmill at 60% of(V)over dot O-2max. Blood samples were collected immediately before the exercise (PRE), immediately following the exercise (POST), and 4 (heart rate (4HR), 12 (12HR), 24 (24HR), and 48 (48HR)) h following the exercise. The variables examined included plasma e rythropoietin concentration ([EPO]), hemoglobin (Hb) concentration ([Hb]), hematocrit (Hct), red blood cell count (RBC), and mean corpuscular volume ( MCV). Results: ANOVA revealed the expected treatment-by-time interaction fo r Hct and [Hb] suggesting a hemodilution at 24 and 48 h postexercise for th e MOD and HIGH treatments. However, no significant treatment-by-time intera ctions were observed for [EPO], RBC, or MCV. Conclusion: These results indi cate that intermittent high intensity exercise does not have a significant effect on [EPO] in trained distance runners.