Journal of Sports Science and Medicine
Journal of Sports Science and Medicine
ISSN: 1303 - 2968   
Ios-APP Journal of Sports Science and Medicine
Androit-APP Journal of Sports Science and Medicine
Views
3131
Download
170
from September 2014
 
©Journal of Sports Science and Medicine (2007) 06, 265 - 266

Letter to editor
Hemoglobin and Hematocrit During an 8 Day Mountainbike Race: a Field Study
Katharina C. Wirnitzer , Martin Faulhaber
Author Information
University of Innsbruck, Austria

Katharina C. Wirnitzer
✉ Department of Sport Science, University of Innsbruck, Austria.
Email: katharina@wirnitzer.at
Publish Date
Received: 24-01-2007
Accepted: 28-02-2007
Published (online): 01-06-2007
Share this article
 

Dear Editor-in-chief

Considering the fact that mountainbike (MTB) marathon and ultraendurance events also as MTB stage races have become very popular during the last decade knowledge is sparse about the effects on hematological system due to prolonged strenuous exercise. Endurance trained athletes generally show an increased blood volume mainly due to plasma volume (PV) expansion, which already exerts after a few days of prolonged exercise, accompanied by lower hemoglobin (Hb) and hematocrit (Hct) levels. On a short term basis dehydration caused by prolonged exertive exercise leads to enhanced concentrations of Hb and Hct due to decreased PV. In contrast to acute exercise it has been well documented as a long term adaptation that regular endurance training over long term periods or repeated bouts of strenuous exercise, e. g. repetitive cycling races or cycling stage races over several consecutive days, lead to a fall in both Hb and Hct levels due to a progressive enlargement in particular in PV. Changes in hematological parameters are known to considerably influence physical performance, especially in aerobic endurance sports such as mountainbiking. An increase in PV normally results in enhanced aerobic performance due to reduced blood viscosity, thereby optimized microcirculation and improved oxygen delivery capacity to the working muscle (Schumacher et. al., 2000). Hematological parameters Hb and Hct are highly sensible to acute effects. The effects of prolonged exercise on hematological status are mainly dependent on total load (mode and duration) of exercise, as well as thermal stress (temperature and humidity) and fluid intake (FI) (Convertino, 1991; Fellmann et. al., 1999; Neumayr et. al., 2002; Sawka et. al., 2000; Schumacher et. al., 2000). The Transalp Challenge (TAC) is one of the hardest MTB marathon races in the world (besides Cape Epic/SA and Transrockies/USA), covering eight consecutive stages. The key data of TAC 2004 are: 22. 500 m (altitude difference), 662 km (distance), which reflects a daily average of 2.812,5 m along with 82.75 km. Therefore, the aim of this study was to determine development and changes in haematological variables Hb, Hct and PV during this MTB stage race.

Six MTB athletes (5 male, 1 female - non professional, reliably not being doped) participated in the field study (Table 1), which was performed according to the Declaration of Helsinki. When exclusively professional cyclists are studied the risk of obtaining falsified data influenced by any kind of doping should be considered. Blood samples were drawn (E0: baseline levels pre race, post exercise values 5 to 10 minutes after individual finish of stages E1, E4, E6) after five minutes of rest in supine position to determine Hb and Hct levels (Miniphotometer plus LP 20, Lange/Germany). Blood samples derived from capillary finger tip. The amount of daily FI including breakfast was recorded by questionnaire immediately after individual finishes (down to an accuracy of 125 ml). Relative changes in PV (∆%PV) were calculated from pre- and post exercise values of Hb and Hct according to the equation of Strauss et. al. (1951): ∆%PV = 100 (Hbpre/Hbpost) (1-Hctpost/1-Hctpre) . Parameters were analysed by using SPSS software package, version 11.0 (Chicago, Illinois, USA). Changes in both Hb (∆Hb) and Hct (∆%Hct) were calculated by paired t test, correlations were computed by Pearson`s correlation coefficient (r). Values are presented as means ± SD. P-values 0.05 were considered to indicate statistical significance.

This field study detected a significant increase in Hb and Hct after the first stage of TAC 2004 while the impact on calculated PV is pronounced. In the course of the race values of both Hb and Hct decreased significantly, PV was calculated to be expanded. Schmidt et. al. (2000) found a similar decline in PV for submaximal load (10.5 %).

The results of the present study reflect that fluid substitution was not effective enough to prevent exercise induced dehydration during E1 (Table 2). Thus, heat elimination by the redistribution of blood flow and body water losses due to sweat and respiration induced a PV decline leading to increased levels of Hb and Hct. (Convertino, 1991; Mounier et. al., 2003; Sawka et. al., 2000; Schmidt et. al., 2000; Schumacher et. al., 2000). In contrast to exercise induced short term effects this field study further points out a significant decline in Hb and Hct during the course of the TAC 2004. Additionally, decrease in Hct was not that markable in former publications as presented in this study: -5.1 % (Schmidt et. al., 2000) and -4.31 % (Mounier et. al., 2003). While long term decreases in Hb and Hct are pronounced, enhancement in PV is calculated not to reach statistical significance. Mounier et. al. (2003) found a similar PV expansion of 8.5 %. Although this field study was only performed on six subjects hemodilutive effects are clearly shown. Convertino, 1991, Fellmann et. al. (1999) and Sawka et. al. (2000) found that PV expansion was maximal on the fourth day of a 7-day ultra endurance race. Until E4 of the TAC 2004 Hb and Hct show a continuous and pronounced fall while PV expansion is pronounced. Hb and Hct readings remained nearly at this lower level while PV remained narrow to this higher level until the end of this MTB race. This field study was done under authentic conditions of the TAC 2004. The authors are absolutely conscious of the fact that method used is not gold standard. The decision had to be made in the light of several unexpected operational and organisational difficulties in participation and accomplishment of this huge 8 days lasting MTB race. It can be concluded that during E1 of the TAC 2004 hemoconcentration was detected to be the acute effect of strenuous endurance impact on hematological parameters. Furthermore, hemodilution was shown as a long term effect of repeated MTB endurance strains.

AUTHOR BIOGRAPHY

Journal of Sports Science and Medicine Katharina C. Wirnitzer
Employment: University of Innsbruck
Degree:
Research interests:
E-mail: katharina@wirnitzer.at
 

Journal of Sports Science and Medicine Martin Faulhaber
Employment: University of Innsbruck
Degree:
Research interests:
E-mail:
 
REFERENCES
Journal of Sports Science and Medicine Convertino V.A. (1991) Blood volume: Its adaption to endurance training. Medicine and Science in Sports and Exercise 13, 1338-1348.
Journal of Sports Science and Medicine Fellmann N., Ritz P., Rubeyre J., Beazfrere B., Delaitre M., Coudert J. (1999) Intracellular hyperhydration induced by a 7-day endurance race. European Journal of Applied Physiology and Occupational Physiology 80, 353-359.
Journal of Sports Science and Medicine Mounier R., Pialoux V., Mischler I., Coudert J., Fellmann N. (2003) Effect of hypervolemia on heart rate during 4 days of prolonged exercise. International Journal of Sports Medicine 24, 523-529.
Journal of Sports Science and Medicine Neumayr G., Pfister R., Mitterbauer G., Gänzer H., Joannidis M., Eibl G., Hörtnagl H. (2002) Short-term effects of prolonged strenuous endurance exercise on the level of haematocrit in amateur cyclists. International Journal of Sports Medicine 23, 158-161.
Journal of Sports Science and Medicine Sawka M.N., Convertino V.A., Eichner E.R., Schnieder S.M., Young A.J. (2000) Blood volume: Importance and adaptions to exercise training, environmental stresses and trauma/sickness. Medicine and Science in Sports and Exercise 32, 332-348.
Journal of Sports Science and Medicine Schmidt W., Biermann B., Winchenbach P., Lison S., Boning D. (2000) How valid is the determination of hematocrit values to detect blood manipulations?. International Journal of Sports Medicine 21, 133-138.
Journal of Sports Science and Medicine Schumacher Y.O., Grathwohl D., Barturen J.M., Wollenweber M., Heinricht L., Schmid A., Huber G., Keul J. (2000) Haemoglobin, haematocrit and red blood cell indices in elite cyclists. Are the control values for blood testing valid?. International Journal of Sports Medicine 21, 380-385.
Journal of Sports Science and Medicine Strauss M.B., Davis R.K., Rosenbaum J.D., Rossmeisl E.C. (1951) Water diuresis produced during recumbency by the intravenous infusion of isotonic saline solution. Journal of Clinical Investigation 30, 862-868.
 
 
 
Home Issues About Authors
Contact Current Editorial board Authors instructions
Email alerts In Press Mission For Reviewers
Archive Scope
Supplements Statistics
Most Read Articles
  Most Cited Articles
 
  
 
JSSM | Copyright 2001-2020 | All rights reserved. | LEGAL NOTICES | Publisher

It is forbidden the total or partial reproduction of this web site and the published materials, the treatment of its database, any kind of transition and for any means, either electronic, mechanic or other methods, without the previous written permission of the JSSM.

This work is licensed under a Creative Commons License Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.