Hotter environments can often alter the normal exercises responses of metabolism and work performance compared to exercise in a more neutral condition. The goal of this study was to determine the effects of a hot (H) and room temperature (RT) environment on glycogen resynthesis during recovery from exercise. Recreationally active males (n = 9) completed two trials, each with 60-min of cycling exercise at 60% of maximum watts in a temperature-controlled chamber (32.6°C), followed by 4 hours of recovery at the same temperature (H) or 22.2°C (RT). Subjects were fed a carbohydrate beverage (1.8 g/kg bodyweight) at 0 and 2 hours post-exercise. Muscle biopsies were taken from the vastus lateralis at 0, 2, and 4 hours post-exercise for analysis of muscle glycogen. Blood samples were collected at 0, 30, 60, 120, 150, 180, and 240 minutes of recovery for glucose and insulin analysis. Ambient and core temperatures were monitored for the duration of the trial. Expired gas was collected prior to 2- and 4-hour biopsies for calculation of whole-body carbohydrate (CHO) oxidation. Glycogen, core temperature, CHO oxidation, and blood marker values were analyzed using two-way ANOVA with repeated measures. Average core temperature was significantly higher in H compared to RT (38.1°C ± 0.01° vs. 37.9°C ± 0.08°, p<0.05) during recovery. Glycogen was not different at 0 and 2 hours post-exercise. However, at 4 hours post-exercise muscle glycogen was significantly higher in RT vs. H (105 ± 28 vs. 88 ± 24 mmolkg-1 wet weight, respectively). Blood glucose levels were similar between H and RT for the first two hours, but showed lower values (p<0.05) in RT compared to H at time points 150, 180, and 240 minutes post-exercise. CHO oxidation during recovery was higher in H compared to RT (0.36 ± 0.04 g/min vs. 0.22 ± 0.03 g/min, respectively, p<0.05), with greater CHO oxidation at 4-hours post-exercise in both trials. Glycogen resynthesis during recovery is impaired in a hot environment, likely due to increased oxidation of CHO instead of synthesis.
| Identifer | oai:union.ndltd.org:MONTANA/oai:etd.lib.umt.edu:etd-06052009-115319 |
| Date | 15 June 2009 |
| Creators | Naperalsky, Michael E. |
| Contributors | Brent Ruby, Ph.D., Arthur Miller, Ph.D., Earle Adams, Ph.D. |
| Publisher | The University of Montana |
| Source Sets | University of Montana Missoula |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.umt.edu/theses/available/etd-06052009-115319/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Montana or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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