Foot-strike haemolysis after a 60-km ultramarathon.
BACKGROUND
The various contributors to sport-related anaemia include increased plasma volume, exercise-induced oxidative stress, increased body temperature, acidosis, gastrointestinal bleeding, acute and chronic inflammation as well as compression and damage of red blood cells (RBC) in the capillaries within the contracting muscles. The effective contribution of foot-strike haemolysis is unclear.


METHODS
We studied 18 Caucasian male athletes (mean age, 42 years; range, 34-52 years) before and immediately after a 60-km ultramarathon. Laboratory investigations included the haematological profile along with haptoglobin, potassium, aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH) and albumin concentrations and a haemolysis index (HI).


RESULTS
No significant variations were found in post-exercise values of haemoglobin, RBC count and haematocrit. Mean corpuscular volume and haptoglobin were significantly decreased, whereas RBC distribution width was increased. The concentration of haptoglobin was reduced by approximately 50%, whereas enzyme concentrations were all remarkably increased. The HI remained below 0.5 g/L. After adjusting for plasma volume change, the increases were 1.7% for potassium (P=0.17), 30% for AST (P<0.01), 49% for LDH (P<0.01) and 2.39-fold for CK (P<0.01). A statistically significant association was found between haemoconcentration-adjusted variations of CK and those of AST (r=0.803; P<0.01) and LDH (r=0.551; P=0.02).


CONCLUSIONS
This is the first study demonstrating that long-distance running does not induce clinically significant changes in haemoglobin, haematocrit, RBC count or potassium concentration. The significant post-exercise decrease of haptoglobin reflects a certain degree of haemolysis, but the concentration of cell-free haemoglobin remaining below 0.5 g/L and the non-significant variation in RBC count both indicate that the foot-strike haemolysis is very modest or even clinically negligible.
Unit of Diagnostic Blood-Chemistry, Department of Pathology and Laboratory Medicine, University Hospital of Parma, Parma, Italy. glippi@ao.pr.it
Giuseppe
G
Lippi
Federico
F
Schena
Gian Luca
GL
Salvagno
Rosalia
R
Aloe
Giuseppe
G
Banfi
Gian Cesare
GC
Guidi
D000328:Adult; D000740:Anemia / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D056352:Athletes; D004906:Erythrocyte Count; D005528:Foot; D006242:Haptoglobins / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D006461:Hemolysis; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D011188:Potassium / Q000097:blood; D012420:Running; D012709:Serum Albumin / Q000378:metabolism
D006242:Haptoglobins; D006454:Hemoglobins; D012709:Serum Albumin; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D011188:Potassium