Oral Communication

Hematological and metabolic changes after a 6-day ultramarathon on indoor cycle and treadmill

Dr Marie THOMAS-POHLa, Dr Stéphane MOUTERAUb, Dr Marc CONTIb, Prof Sylvain LORICb, Dr Etienne JAMES-BELINa, Dr Yves COULOMBa, Prof Jean-Michel GRACIESa

a Fédération neurolocomotrice, Hôpital Albert Chenevier - Henri Mondor, Créteil, b Service de biochimie, Hôpital Henri Mondor, Créteil

Objective: Ultra-endurance events may induce biological changes as a consequence of intense muscle stress and hormonal fluctuations. Two ultra-endurance athletes, one on treadmill, the other on a home trainer pinion, have attempted to break world records for greatest distance covered over 6 days in Paris on January 4-10, 2015 ("six extreme days”). We analyzed the hematological, hormonal and biochemical changes.

Materials and Methods: Hematological, biochemical, hormonologic, metabolic and specific to oxidative stress analysis were conducted on fresh and frozen blood samples collected a week before (D-7), 30 minutes (D6) and 2 days (D8) after the event for both sportsmen. Periods of waking/sleep, cardiovascular data (pulse, saturation) and developed efforts (distance, speed) were monitored throughout the event.

Results: Hemoglobin, hematocrit and iron parameters (serum iron, ferritin, transferrin saturation coefficient) were found lower on D6, after 2750km cycling or 713km running, than on D-7 (hemoglobin decreased from 15.2 g/dl before the event to 13.3 g/dl just after). They start to increase back on D8. Leukocytes (6.5 to 9,4G/l between D-7 and D6), haptoglobin (tripled between D-7 and D8, from 1 to 3 g/l), liver enzymes, CreatinePhosphoKinase, troponin, BrainNatriureticPeptide and uric acid rose during the event before going back down on D8 without however reaching back initial levels.

Discussion: The observed transient anemia is multifactorial, inflammatory, iron deficiency but without here any element for hemolysis. Hepatic cytolysis and heart stress are commonly encountered [1]. No study however focuses on oxidative stress enzymes (glutathione, lipid peroxidation products, activation of xanthine oxidase) after such a long effort, for which mobilization of leukocytes and increased uric acid (antioxidant) are indirect markers [2]. Data from this exploration should help enhancing our understanding of the impact of very prolonged effort on the oxidative stress chain, and paves the way for potential improvement in the training methods of athletes.

References :

1. Kupchak BR et al. The impact of an ultramarathon on hormonal and biochemical parameters in men.Wilderness Environ Med 2014;25:278-88.

2. Groussard C. Stress oxydatif et exercice anaérobie.Science et sports 2006 ;21 :62-67.

Keywords : ultramarathon, oxidative stress, anemia