Daily Hematologic Assessment During a 230-Km Multistage Ultramarathon

Abstract

Introduction: The popularity of ultra-endurance events is increasing worldwide. However, information about hematological parameters during repeated bouts of long-duration running, such as stages during a multi-stage ultramarathon (MSUM) is scarce. Objective: The purpose of the study was to monitor daily hematologic assessment in a 230-km multistage ultramarathon (MSUM) in hot environmental conditions. Methods: Eleven male and three female (n = 14) ultra-endurance runners entered this MSUM, which was conducted over five stages, covering a total distance of 230 km in hot ambient conditions. Peripheral blood samples were collected before and after each stage to determine leukocyte and erythrocytes parameters. Results: Multilevel modelling considering all measurement points showed an increase for whole blood leukocyte and granulocyte counts at five stages of the MSUM and for monocytes until Stage 3 of the race. For erythrocyte parameters, decreases across stages were observed in hemoglobin concentration and hematocrit responses when computing/considering all measurement points. Conclusions: The results indicate that MSUM in a hot environment leads to a greater impact on leukocyte population responses and platelet variation in the initial stages of the race. We suggest that athletes may have a decrease in immune function in the early stages of the MSUM, probably with some transient risk of infectious. Nevertheless, a physiological adaptation to physical exertion and heat mitigates these changes in the subsequent stages of MSUM.

Electrolyte Changes Related to Muscle Pain After Resistance Exercises

“…13 The most commonly evaluated electrolytes are sodium (Na + ), potassium (K + ), calcium (Ca 2+ ) and magnesium (Mg 2+ ), and their alterations can generate electrolyte disturbances, which include dehydration, neuromuscular changes, paresthesias and muscle pain. [13][14][15] The RE on these serum components are influenced by environmental conditions, exercise intensity and effort duration, 16,17 because these factors influence dehydration, which reduces the amount of bioavailable electrolytes during exercise. 18 In this context, electrolyte alterations after RE have been little studied yet, although these evaluations are extremely important to develop appropriate measures for rehydration and the possible prevention of discomfort after these exercises.…”