Biological and body composition alterations induced by an ultramarathon in kayak: a case study

Abstract

Long lasting exertion induced stress can alter body homeostasis that can remain visible during several days and seem to be dependent from the training level of the subjects. This study intended to assess biochemical and body composition alterations induced by an ultramarathon in kayak. The subject was a male master kayaker, aged 48 years old and with near 30 years of continuous practice of kayaking. The ultramarathon was performed in River Douro, from Duruelo de la Sierra (Spain) till Oporto (Portugal), covering almost 1000 km within 17 days. Daily exertion varied from 55 km (the shortest stage) to 85 km (the longest stage). Body composition was assessed from skinfolds measurements; after an overnight fast blood samples were collected from antecubital vein, at rest, before and several moments after the ultramarathon. Some biological parameters (enzimes, electrolytes, clooting factors, blood chemistry) were assessed. It was stated a significant reduction of body weight and fat mass percent. The most significant alterations of biological indicators were, serum iron decrease and HDLc increase. . High basal values of urea and creatinina (some of them out of laboratorial reference) are unlikely related to the ultramarathon. Serum enzymes, evolving within the limits of laboratorial normality indicated absence of rabdomiólisis or hepatic and epithelial cell destruction. Other minerals studied (Ca, Na, K, Mg, Cl, P) evolved within the standard of normality. The low values of the coagulation indicators demonstrated a certain protection against thrombogenecity with low values of fibrinogen and low values of several clotting factors (II, V, VII, X), while clotting times were maintained within the values of laboratorial normality. The kayak ultramarathon, perhaps by the subjects’ high training level, didn’t induce alterations which can be considered as pathological, indicating good accommodation of the master kayaker to this kind of exertion.