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 intensity running on plasma erythropoietin concentration in competitive distance runners. A repeated measures design was used to compare the responses of intermittent high intensity (HIGH) exercise to continuous moderate intensity (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 continuous 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 erythropoietin 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 for Hct and [Hb] suggesting a hemodilution at 24 and 48 h postexercise for the MOD and HIGH treatments. However, no significant treatment-by-time interactions were observed for [EPO], RBC, or MCV. Conclusion: These results indicate that intermittent high intensity exercise does not have a significant effect on [EPO] in trained distance runners.