Browsing by Author "Hew-Butler, Tamara"

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    Drinking during marathon running in extreme heat: A video analysis study of the top finishers in the 2004 Athens Olympic marathons
    (2010) Hew-Butler, Tamara; Van Rooyen, Michele; Noakes, Timoth
    Objective. To assess the drinking behaviours of top competitors during an Olympic marathon. Methods. Retrospective video analysis of the top four finishers in both the male and female 2004 Athens Olympic marathons plus the pre-race favourite in the female race in order to assess total time spent drinking. One male and female runner involved in a laboratory drinking simulation trial. Results. For the five female athletes, 37 of a possible 73 drinking episodes were captured. The female race winner was filmed at 11 of 15 drinking stations. Her total drinking time was 23.6 seconds; extrapolated over 15 seconds this would have increased to 32.2 seconds for a total of 27 sips of fluid during the race. Eighteen of a possible 60 drinking episodes for the top four male marathon finishers were filmed. The total drinking time for those 18 episodes was 11.4 seconds. A laboratory simulation found that a female athlete of approximately the same weight as the female Olympic winner might have been able to ingest a maximum of 810 ml (350 ml.h-1) from 27 sips whilst running at her best marathon pace whereas a male might have drunk a maximum of 720 ml (330 ml.h-1) from 9 sips under the same conditions. Conclusions. These data suggest that both the female and male 2004 Olympic Marathon winners drank minimal total amounts of fluid (<1 litre) in hot (>30ºC) temperatures while completing the marathon with race times within 2.5% of the Olympic record.
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    Dysnatremia and the endocrine regulation of fluid balance during exercise
    (2007) Hew-Butler, Tamara; Noakes, Tim; Verbalis, Joseph G
    The aim of this thesis is to evaluate both abnormal and normal fluid balance during exercise. The central theme permeating all investigations is an underlying desire to understand exercise-associated hyponatremia. This thesis reflects a journey of scientific investigation primarily launched by outcomes from the 1st International Consensus Development Conference on Exercise-Associated Hyponatremia. Each individual investigation directly follows from the results of the previous investigation. Hence, the journey towards a greater understanding of exercise-associated hyponatremia went full circle and ultimately encompassed the spectrum of fluid regulation and dysregulation during exercise. This thesis begins with a brief overview of the literatur which services to intertwine previous knowledge with new knowledge gained from each successive study. A review of the literature on exercise-associated hyponatremia opens the first chapter and lays the foundation for the follwoing eight investigations. This thesis closes with a final summary of the literature which defends fluid balance physiology as the ultimate guide for developing more "physiologically appropriate" fluid replacement strategies. More specifically, the first two chapters document the abnormal regulation of serum sodium concentration during exercise.