Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities
This study examined the effects of pre-exercise carbohydrate availability on the time to exhaustion for moderate and heavy exercise. Seven men participated in a randomized order in two diet and exercise regimens each lasting 3 days with a 1-week interval for washout. The tests were performed at 50%...
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| Format: | Article |
| Language: | English |
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Associação Brasileira de Divulgação Científica
2009-05-01
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| Series: | Brazilian Journal of Medical and Biological Research |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000500002 |
| _version_ | 1811299961232424960 |
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| author | A.E. Lima-Silva F.R. De-Oliveira F.Y. Nakamura M.S. Gevaerd |
| author_facet | A.E. Lima-Silva F.R. De-Oliveira F.Y. Nakamura M.S. Gevaerd |
| author_sort | A.E. Lima-Silva |
| collection | DOAJ |
| description | This study examined the effects of pre-exercise carbohydrate availability on the time to exhaustion for moderate and heavy exercise. Seven men participated in a randomized order in two diet and exercise regimens each lasting 3 days with a 1-week interval for washout. The tests were performed at 50% of the difference between the first (LT1) and second (LT2) lactate breakpoint for moderate exercise (below LT2) and at 25% of the difference between the maximal load and LT2 for heavy exercise (above LT2) until exhaustion. Forty-eight hours before each experimental session, subjects performed a 90-min cycling exercise followed by 5-min rest periods and a subsequent 1-min cycling bout at 125% VO2max/1-min rest periods until exhaustion to deplete muscle glycogen. A diet providing 10% (CHOlow) or 65% (CHOmod) energy as carbohydrates was consumed for 2 days until the day of the experimental test. In the exercise below LT2, time to exhaustion did not differ between the CHOmod and the CHOlow diets (57.22 ± 24.24 vs 57.16 ± 25.24 min). In the exercise above LT2, time to exhaustion decreased significantly from 23.16 ± 8.76 min on the CHOmod diet to 18.30 ± 5.86 min on the CHOlow diet (P < 0.05). The rate of carbohydrate oxidation, respiratory exchange ratio and blood lactate concentration were reduced for CHOlow only during exercise above LT2. These results suggest that muscle glycogen depletion followed by a period of a low carbohydrate diet impairs high-intensity exercise performance. |
| first_indexed | 2024-04-13T06:43:24Z |
| format | Article |
| id | doaj.art-e4e6bb0a7c1d4514bf6687ada7f90751 |
| institution | Directory Open Access Journal |
| issn | 0100-879X 1414-431X |
| language | English |
| last_indexed | 2024-04-13T06:43:24Z |
| publishDate | 2009-05-01 |
| publisher | Associação Brasileira de Divulgação Científica |
| record_format | Article |
| series | Brazilian Journal of Medical and Biological Research |
| spelling | doaj.art-e4e6bb0a7c1d4514bf6687ada7f907512022-12-22T02:57:40ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research0100-879X1414-431X2009-05-0142540441210.1590/S0100-879X2009000500002Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensitiesA.E. Lima-SilvaF.R. De-OliveiraF.Y. NakamuraM.S. GevaerdThis study examined the effects of pre-exercise carbohydrate availability on the time to exhaustion for moderate and heavy exercise. Seven men participated in a randomized order in two diet and exercise regimens each lasting 3 days with a 1-week interval for washout. The tests were performed at 50% of the difference between the first (LT1) and second (LT2) lactate breakpoint for moderate exercise (below LT2) and at 25% of the difference between the maximal load and LT2 for heavy exercise (above LT2) until exhaustion. Forty-eight hours before each experimental session, subjects performed a 90-min cycling exercise followed by 5-min rest periods and a subsequent 1-min cycling bout at 125% VO2max/1-min rest periods until exhaustion to deplete muscle glycogen. A diet providing 10% (CHOlow) or 65% (CHOmod) energy as carbohydrates was consumed for 2 days until the day of the experimental test. In the exercise below LT2, time to exhaustion did not differ between the CHOmod and the CHOlow diets (57.22 ± 24.24 vs 57.16 ± 25.24 min). In the exercise above LT2, time to exhaustion decreased significantly from 23.16 ± 8.76 min on the CHOmod diet to 18.30 ± 5.86 min on the CHOlow diet (P < 0.05). The rate of carbohydrate oxidation, respiratory exchange ratio and blood lactate concentration were reduced for CHOlow only during exercise above LT2. These results suggest that muscle glycogen depletion followed by a period of a low carbohydrate diet impairs high-intensity exercise performance.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000500002Time to exhaustionMuscle glycogenMetabolismLactate thresholds |
| spellingShingle | A.E. Lima-Silva F.R. De-Oliveira F.Y. Nakamura M.S. Gevaerd Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities Brazilian Journal of Medical and Biological Research Time to exhaustion Muscle glycogen Metabolism Lactate thresholds |
| title | Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities |
| title_full | Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities |
| title_fullStr | Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities |
| title_full_unstemmed | Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities |
| title_short | Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities |
| title_sort | effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities |
| topic | Time to exhaustion Muscle glycogen Metabolism Lactate thresholds |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000500002 |
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