Glykogeninlagring

[Arwen]

Ngn som kan ge en snabb upskattning av tiden från intag av kolhydrater (tex pasta) tills dess att de lagrats som glykogen i musklerna?

1 timme, 12 timmar, 24 timmar?

[King Grub]

Aust J Sci Med Sport. 1997 Mar;29(1):3-10.

Nutrition for post-exercise recovery.

Burke LM.

Australian Institute of Sport, ACT, Australia.

Recovery after exercise poses an important challenge to the modern athlete. Important issues include restoration of liver and muscle glycogen stores, and the replacement of fluid and electrolytes lost in sweat. Rapid resynthesis of muscle glycogen stores is aided by the immediate intake of carbohydrate (I g.kg-1 BM each 2 hours), particularly of high glycemic index carbohydrate foods, leading to a total intake over 24 hours of 7-10 g.kg-1 BM. Provided adequate carbohydrate is consumed it appears that the frequency of intake, the form (liquid versus solid) and the presence of other macronutrients does not affect the rate of glycogen storage.

[King Grub]

Int J Sports Med. 1998 Jun;19 Suppl 2:S142-5.

Glycogen resynthesis after exercise: effect of carbohydrate intake.

Ivy JL.

Department of Kinesiology, University of Texas, Austin 78712, USA

To maximize glycogen resynthesis after exercise, carbohydrate in excess of 1.0 g x kg(-1) body wt should be consumed immediately after competition or a training bout. Continuation of supplementation every two hours will maintain a rapid rate of storage up to six hours post exercise. Supplements composed of glucose or glucose polymers are the most effective for replenishment of muscle glycogen, whereas fructose is most beneficial for the replenishment of liver glycogen. The addition of protein to a carbohydrate supplement may also increase the rate of glycogen storage due to the ability of protein and carbohydrate to act synergistically on insulin secretion.

[King Grub]

Sports Med. 2003;33(2):117-44.

Determinants of post-exercise glycogen synthesis during short-term recovery.

Jentjens R, Jeukendrup A.

Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, UK.

The pattern of muscle glycogen synthesis following glycogen-depleting exercise occurs in two phases. Initially, there is a period of rapid synthesis of muscle glycogen that does not require the presence of insulin and lasts about 30-60 minutes. This rapid phase of muscle glycogen synthesis is characterised by an exercise-induced translocation of glucose transporter carrier protein-4 to the cell surface, leading to an increased permeability of the muscle membrane to glucose. Following this rapid phase of glycogen synthesis, muscle glycogen synthesis occurs at a much slower rate and this phase can last for several hours. Both muscle contraction and insulin have been shown to increase the activity of glycogen synthase, the rate-limiting enzyme in glycogen synthesis. Furthermore, it has been shown that muscle glycogen concentration is a potent regulator of glycogen synthase. Low muscle glycogen concentrations following exercise are associated with an increased rate of glucose transport and an increased capacity to convert glucose into glycogen.The highest muscle glycogen synthesis rates have been reported when large amounts of carbohydrate (1.0-1.85 g/kg/h) are consumed immediately post-exercise and at 15-60 minute intervals thereafter, for up to 5 hours post-exercise. When carbohydrate ingestion is delayed by several hours, this may lead to ~50% lower rates of muscle glycogen synthesis. The addition of certain amino acids and/or proteins to a carbohydrate supplement can increase muscle glycogen synthesis rates, most probably because of an enhanced insulin response. However, when carbohydrate intake is high (> or =1.2 g/kg/h) and provided at regular intervals, a further increase in insulin concentrations by additional supplementation of protein and/or amino acids does not further increase the rate of muscle glycogen synthesis. Thus, when carbohydrate intake is insufficient (<1.2 g/kg/h), the addition of certain amino acids and/or proteins may be beneficial for muscle glycogen synthesis. Furthermore, ingestion of insulinotropic protein and/or amino acid mixtures might stimulate post-exercise net muscle protein anabolism. Suggestions have been made that carbohydrate availability is the main limiting factor for glycogen synthesis. A large part of the ingested glucose that enters the bloodstream appears to be extracted by tissues other than the exercise muscle (i.e. liver, other muscle groups or fat tissue) and may therefore limit the amount of glucose available to maximise muscle glycogen synthesis rates. Furthermore, intestinal glucose absorption may also be a rate-limiting factor for muscle glycogen synthesis when large quantities (>1 g/min) of glucose are ingested following exercise.

[Sverker]

King Grub har svar på allt:D



Kul att se " Furthermore, intestinal glucose absorption may also be a rate-limiting factor for muscle glycogen synthesis when large quantities (>1 g/min) of glucose are ingested following exercise."


Vilket jag påstår ibland, att det är tarmarna som begränsar upptaget av glukos. De siffror jag har tillgång till är 80 - 100 g / timme vilket är lite högre än Kungens siffror ( 60 g / timme ).


Tänker man praktiskt när det gäller glykogeninlagring, de som kolhydratladdar för Vasaloppet eller en byggartävling laddar ju rejält med kolhydrat i två, ibland tre dagar innan kroppen är helt fylld.
Här gäller ju inte att fylla upp från 0 g till 5 - 10 g / kg muskelmassa utan rejält överladda till 25 - 30 g glykogen / kg muskelmassa.