Effect of a 2-h hyperglycemic-hyperinsulinemic glucose clamp to promote glucose storage on endurance exercise performance.
- Resource Type
- journal article
- Authors
- MacLaren, D. P. M.; Mohebbi, H.; Nirmalan, M. A.; Keegan, M. A.; Best, C. T.; Perera, D.; Harvie, M. N.; Campbell, I. T.; Nirmalan, M
- Source
- European Journal of Applied Physiology. Aug2011, Vol. 111 Issue 9, p2105-2114. 10p. 1 Chart, 5 Graphs.
- Subject
- *ENDURANCE sports
*GLUCOSE
*HYPERGLYCEMIA
*OXYGEN consumption
*PHYSIOLOGICAL transport of carbon dioxide
*CYCLING
*PHYSIOLOGY
*GLUCOSE metabolism
*ATHLETIC ability
*BIOCHEMISTRY
*BIOLOGICAL transport
*BLOOD sugar
*COMPARATIVE studies
*EXERCISE
*HYPERINSULINISM
*INSULIN
*PHENOMENOLOGY
*RESEARCH methodology
*MEDICAL cooperation
*PHYSICAL fitness
*RESEARCH
*TIME
*EVALUATION research
*GLUCOSE clamp technique
- Language
- ISSN
- 1439-6319
Carbohydrate stores within muscle are considered essential as a fuel for prolonged endurance exercise, and regimes for enhancing such stores have proved successful in aiding performance. This study explored the effects of a hyperglycaemic-hyperinsulinemic clamp performed 18 h previously on subsequent prolonged endurance performance in cycling. Seven male subjects, accustomed to prolonged endurance cycling, performed 90 min of cycling at ~65% VO(2max) followed by a 16-km time trial 18 h after a 2-h hyperglycemic-hyperinsulinemic clamp (HCC). Hyperglycemia (10 mM) with insulin infused at 300 mU/m(2)/min over a 2-h period resulted in a total glucose uptake of 275 g (assessed by the area under the curve) of which glucose storage accounted for about 73% (i.e. 198 g). Patterns of substrate oxidation during 90-min exercise at 65% VO(2max) were not altered by HCC. Blood glucose and plasma insulin concentrations were higher during exercise after HCC compared with control (p < 0.05) while plasma NEFA was similar. Exercise performance was improved by 49 s and power output was 10-11% higher during the time trial (p < 0.05) after HCC. These data suggest that carbohydrate loading 18 h previously by means of a 2-h HCC improves cycling performance by 3.3% without any change in pattern of substrate oxidation. [ABSTRACT FROM AUTHOR]