Date of Completion

5-11-2013

Embargo Period

4-1-2013

Advisors

Lawrence E. Armstrong, Carl M. Maresh, Rebecca L. Stearns

Field of Study

Kinesiology

Degree

Master of Science

Open Access

Open Access

Abstract

Context: Dehydration can negatively impact aerobic performance. Objective: To observe the effect of hydration status on Ironman Triathlete performance and their ability to maintain pace; and to observe the effect of hydration status on pacing and performance for athletes who monitor heart rate for pacing feedback. Design: Observational ironman triathlon study Setting: Lake Placid Ironman racecourse (WBGT, 22.1±2.0 °C). Participants: 41 (30 males, 7 females) triathletes (age, 39±7 yrs; height, 174.0±9.9 cm; pre-race weight, 72.4±10.1 kg; body fat, 15.3±5.6%.) divided into groups based on use(HR) or no use(NHR) of heart rate as pacing feedback, and hydrated(HY) or dehydrated(DHY); based on post race hydration levels. Those who used heart rate were also divided into hydrated(HRH) and dehydrated(HRD) groups. Main Outcome Measures: hydration (urine specific gravity (USG), percent body mass loss (%BML)), pacing (average pace, percent deviation from average pace, percent of overall time spent in each course loop), and physiological responses (gastro-intestinal temperature (Tgi), average heart rate (HR)). Results: An overall effect of time over all loops was seen for both HY and DHY groups on overall pace (p<0.001), pace by percentage of overall time (p<0.001) and percent deviation of pace (from overall average) (p<0.001); but no group by time interaction was observed (p>0.05). An overall effect of time on average heart rate was seen during the bike (p=0.002) and run (p=0.014) sections for the HY and DHY groups, but no group by time interaction occurred (p>0.05). An overall effect of time was observed on overall pace (p<0.001), pace by percentage (p<0.001), and percent deviation of pace (p=0.013). An overall effect of time on average heart rate was observed for the HRH and HRD groups (p=0.014), but no group by time interaction was present (p>0.05). Conclusion: The observed levels of dehydration and minimal differences in BML did not cause significant differences in overall performance and pacing when compared to hydrated subjects. Consideration should still be given to potential improvements that may occur with improved hydration of the dehydrated group.

Major Advisor

Douglas J. Casa

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