HAEMATOLOGICAL PARAMETERS IN SWIMMERS Daniel Gerrard BMedLabSci David Gerrard MBChB Dunedin School of Medicine, U of Otago New Zealand

APPLIED SCIENCE CLINICAL INTERFACE  “Coaches and scientists seeking measures of enhanced performance balanced by clinicians searching for indicators of failing adaptation and consequent ill-health...”

INTRODUCTORY COMMENTS  Endurance training  Red Blood Cell (RBC) genesis, turnover  Anaemia  Haptoglobin function

POSTULATE  “That endurance-trained athletes show haematological evidence of enhanced oxygen transport.”

POSTULATE  “That endurance training is characterised by a younger RBC population”

STUDY AIMS  To establish haematological parameters for two, age-dependent cohorts of male swimmers & compare these with established laboratory normal values.

SUBJECTS SUBJECTS  Endurance-trained males  Masters group “M” (n=11, mean age 58yrs)  Youth group “Y” (n=20, mean age 22.1yrs)  Pooled group “M+Y” (n=31, mean age 35yrs)

METHODS METHODS  Venous blood samples drawn  Participants recruited from local swim squads.  Endurance training criteria applied  University of Otago ethical approval

HAEMATOLOGICAL MEASURES HAEMATOLOGICAL MEASURES  Venous samples  RBC indices  Hb concentration  Haematocrit  TWCC  Reticulocyte count  Serum Haptoglobin

RESULTS  Significant inter-age differences  Compared to “normal” values there was:  Decrease in RBC parameters, Hb,Hct,haptoglobin levels  Increase in MCV (“runners’ macrocytosis”)  Reduced reticulocytes

ENDURANCE TRAINING (1)  Physiological adaptations…  Influence on cardio- respiratory efficiency…  Improved efficiency of oxygen delivery

ENDURANCE TRAINING (2)  Mechanical trauma to RBCs  Altered cell membrane fragility  Haemolysis  Reduced Haptoglobin levels  Younger RBC population

RED BLOOD CELL ROLE  O 2 transport  Haemoglobin (Hb)  4 globin subunits (alpha + beta)  Porphyrin molecule = Haem  Binds iron  4 haeme molecules per Hb molecule

RBC PRODUCTION  Regulated by Erythropoietin (EPO)  Reticulocytes from bone marrow  RBC lifespan days  1% replaced daily  Haemolysis = erythropoiesis  Constant RBC mass

INFLUENCES on RBCs INFLUENCES on RBCs  Metabolic, mechanical, oxidative stresses  Reduced lifespan  Increased immature population of RBCs  Anaemia (hypoxia) Destruction > synthesis  ? Optimal haematological parameters for athletes

ANAEMIA ANAEMIA  Decrease in RBC mass  Link with diminished athletic performance  Dilutional anaemia  Intravascular haemolysis (mechanical)  Dietary iron (nutritional)  Haeme & non-haeme sources

HAPTOGLOBIN HAPTOGLOBIN  Acute phase plasma protein  Binds Hb from haemolysed RBCs  Hapt-Hb complexes  Hepatic removal  Resultant decreased serum Hapt levels  Inversely related to intravascular haemolysis

CONCLUSIONS (1)  That the dilutional anaemia of exercise is the result of more than a simple expanded plasma volume.

CONCLUSIONS (2)  That rising haptoglobin levels may provide a useful index of endurance training.

CONCLUSIONS (3)  An increased RBC turnover may explain the association between a younger RBC population & increased oxygen delivery.

CONCLUSIONS (4)  Further research is indicated to determine the effects of endurance training & age on haematological parameters.

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