Effects of timing of pre-exercise ingestion of carbohydrate on subsequent metabolism and cycling performance.

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The occurrence of rebound hypoglycaemia may depend on the timing of carbohydrate intake. The aim of the present study was to investigate the metabolic and performance responses to the ingestion of carbohydrate at differing times before exercise. Eight subjects [mean (SEM)] [28 (3) years, 74.5 (2.6) kg, maximal oxygen uptake 63.1 (3.1) ml.kg(-1).min(-1)] performed three experiments. They ingested 75 g glucose dissolved in 500 ml water, thereafter resting for either 15, 45 or 75 min (15-Pre, 45-Pre and 75-Pre) before exercising for 20 min at 65% maximal power output followed by a time trial [total work 685 (18) kJ]. There were no differences in performance between conditions [mean powers 268 (10), 269 (7) and 276 (12) W for 15-Pre, 45-Pre and 75-Pre, respectively]. There were significant differences in plasma glucose concentration between 15-Pre [6.6 (0.6) mmol.l(-1); P


Original languageEnglish
Pages (from-to)453-8
Number of pages6
JournalEuropean Journal of Applied Physiology
Issue number4-5
Publication statusPublished - 1 Jan 2003


  • hypoglycaemia, carbohydrate, performance, insulin, glucose