Glykogensyntes efter träning med glukos+fruktos/sackaros jämfört med bara glukos

[King Grub]

Background:

Post-exercise muscle glycogen repletion is largely determined by the systemic availability of exogenous carbohydrate provided.

Purpose:

This study aimed to assess the effect of the combined ingestion of fructose and glucose on post-exercise muscle glycogen repletion when optimal amounts of carbohydrate are ingested.

Methods:

Fourteen male cyclists (age: 28+/-6 y; Wmax: 4.8+/-0.4 W[middle dot]kg-1) were studied on 3 different occasions. Each test day started with a glycogen-depleting exercise session. This was followed by a 5 h recovery period, during which subjects ingested 1.5 g[middle dot]kg-1[middle dot]h-1 glucose (GLU), 1.2 g[middle dot]kg-1[middle dot]h-1 glucose + 0.3 g[middle dot]kg-1[middle dot]h-1 fructose (GLU+FRU), or 0.9 g[middle dot]kg-1[middle dot]h-1 glucose + 0.6 g[middle dot]kg-1[middle dot]h-1 sucrose (GLU+SUC). Blood samples and gastrointestinal distress questionnaires were collected frequently and muscle biopsies were obtained at 0, 120, and 300 min after cessation of exercise to measure muscle glycogen content.

Results:

Plasma glucose responses did not differ between treatments (ANOVA, P=0.096), but plasma insulin and lactate concentrations were elevated during GLU+FRU and GLU+SUC when compared to GLU (P<0.01). Muscle glycogen content immediately following exercise averaged 207+/-112, 219+/-107 and 236+/-118 mmol[middle dot]kg-1 dry weight in the GLU, GLU+FRU and GLU+SUC treatment, respectively (P=0.362). Carbohydrate ingestion increased muscle glycogen concentrations during 5 h of post-exercise recovery to 261+/-98, 289+/-130 and 315+/-103 mmol[middle dot]kg-1 dry weight in the GLU, GLU+FRU and GLU+SUC treatment, respectively (P<0.001), with no differences between treatments (time x treatment, P=0.757).

Conclusion:

Combined ingestion of glucose plus fructose does not further accelerate post-exercise muscle glycogen repletion in trained cyclists when ample carbohydrate is ingested. Combined ingestion of glucose (polymers) plus fructose or sucrose reduces gastrointestinal complaints when ingesting large amounts of carbohydrate

Medicine & Science in Sports & Exercise. November 24, 2015.Fructose Coingestion Does Not Accelerate Postexercise Muscle Glycogen Repletion.

[Gerdler]

Det uppmättes skillnad men den var inte signifikant alltså? Det beror väl rimligtvis på att det är en för liten studie. Dels så är det troligen något bättre men det är också möjligt att på grund av den förbättrade "magkänslan" samt det förbättrade upptaget inta mer på samma tid eller samma mängd på kortare tid.