NO EFFECT OF KETOSIS AND DEHYDRATION ON BORG RATING OF PERCEIVED EXERTION DURING A 50 KM MOUNTAIN ULTRA-MARATHON
PURPOSE: The purpose of this study was to assess if runners who produced ketones and were dehydrated gave greater Borg Ratings of Perceived Exertion (BRPE) during a 50 km mountain ultra-marathon. HYPOTHESIS: It was hypothesized that the increase of BPRE would be greater in the ketone production group as compared to non-ketone producing group. METHODS: Sixteen healthy adults volunteered for this study. Their average age was 44.1+9.4 y (mean±SD), height 1.8+0.1 m, body mass 72.5+9.2 kg, BMI 23.0+2.6 kg•m-2. The office of research ethics at SFU approved the study and each volunteer gave a signed consent prior to participation. Each volunteer provided a pre-race urine sample and BRPE (unit less), then completed a 50 km mountain ultra-marathon, with 3 additional BRPE assessments during the race, and then gave a post-race urine sample and a final BRPE. Qualitative and semi-qualitative urine stripes were used to determine ketone presence in urine samples and urine specific gravity was measured with urinometer. A mixed model ANOVA was employed with the main effects of Distance (0%, 25%, 50%, 75% and 100% of 50 km) and Ketosis State (Ketone Producing and Non-Ketone Producing). The P-value was set at 0.05. RESULTS: Six participants were found to produce ketones in post-race urine samples and were dehydrated with a post-race urine specific gravity of 1.031. Ten participants were found to not produce ketones with a post-race urine specific gravity of 1.019. There was a significant difference in urine specific gravity between the ketone and non-ketone producing group (p<0.05). There was a significant main effect of Distance (F=6.2, p<0.01) on BRPE but no main effect of Ketosis State nor an interaction (F=1.8, p=0.20) between Distance and Ketosis State. The mean BRPE across groups (n=16) ranged from 7.0±1.2 at the start to 15.1±4.4 at the end of the race. CONCLUSION: These preliminary results suggest factors other than ketone production and the associated dehydration cause a rise in BPRE during the course of a mountain ultra-marathon.
Supported by the Natural Sciences and Engineering Research Council of Canada and The Canadian Foundation for Innovation
Singh, P. K.; Rogers, M. J.; Sahota, S. S.; Willie, E. S.; Sidhu, A. H.; Phull, E.; Foster, I. J.; Ngo, M. L.; Rietchel, L. J.; Sandberg, O. A.; Sangha, S. S.; and White, M. D.
"NO EFFECT OF KETOSIS AND DEHYDRATION ON BORG RATING OF PERCEIVED EXERTION DURING A 50 KM MOUNTAIN ULTRA-MARATHON,"
International Journal of Exercise Science: Conference Proceedings: Vol. 8
, Article 32.
Available at: http://digitalcommons.wku.edu/ijesab/vol8/iss5/32
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