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DAILY HEMATOLOGIC ASSESSMENT DURING A 230-KM MULTISTAGE ULTRAMARATHON

AVALIAÇÃO HEMATOLÓGICA DIÁRIA DURANTE UMA ULTRAMARATONA DE MÚLTIPLOS ESTÁGIOS DE 230 KM

EVALUACIÓN HEMATOLÓGICA DIARIA DURANTE UNA ULTRAMARATÓN DE MÚLTIPLES ETAPAS DE 230 KM

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. Level of Evidence III; Case-control study.

Keywords:
Leukocytes; Erythrocytes; Running; Infection; Athletes.

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