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Directly following exercise you have about a 2 hour period in which to
maximise the uptake of glycogen into the body, and hence increase the
rate of glycogen replenishment throughout the body. This window of
opportunity gradually reduces within this 2 hour period and so the
sooner you eat the right carbohydrates, the quicker the recovery will
be.
Following this 2 hour
window of opportunity it is generally accepted that under optimal
carbohydrate intake levels the rate of glycogen replenishment will be
about 5% per hour. Thus, even under the best of circumstances, it
requires at least 20 hours to re-establish glycogen stores after a
glycogen depleting exercise bout. The emphasis here is on the word, "
depleting ", as many sports people will not have completely depleted
their glycogen stores, and so it will take them less than 20 hours to
re-establish glycogen stores.
During this 2 hour
period directly following exercise glycogen replenishment will be
greater than 5%, although It should be noted that a specific amount of
glycogen uptake during this 2 hour period cannot be given.
However, the sooner
carbohydrates are consumed following exercise, the quicker the
recovery will be, and the greater the glycogen replenishment will be,
due to the increased sensitivity of the liver following exercise, and
vice versa.
When the livers
sensitivity is at its highest it will recognise all incoming
carbohydrates, whether in simple or complex form, and it will do its
best to channel it in simple glucose units around the body and then
send the rest into storage through glycogenisis.
Therefore in terms of
energy production for elite level athletes, it is essential to consume
carbohydrates that are as high up as possible on the glycaemic index
in order to facilitate as much glycogen replenishment within this
crucial 2 hour period directly following exercise as possible, and as
quickly as possible. These foods include foods such as white bread,
white pasta, etc.
The reason for
consuming mainly high glycaemic carbohydrates during this 2 hour
period, instead of moderate or low glycaemic carbohydrates, is that in
order to facilitate glycogen replenishment the carbohydrates need to
get into the system as quickly as possible.
The problem which
arises with regards sports performance is regarding the choice of
carbohydrates following training this 2 hour window of opportunity.
Following this 2 hour period, in which carbohydrates replenish at such
a slow and steady rate, it is then advisable to eat a mixture of
foods, and moderate to low glycaemic index carbohydrates, as these
will then allow for a much more steady, and progressive rate of
digestion, and hence provide a continuous uptake of carbohydrates, and
other nutrients, ensuring that you get that glycogen replenishment of
about 5% per hour, which will happen to a lesser degree if you are
still eating just high glycaemic foods.
It is important to note
that a person’s glycogen reserves will be replenished more rapidly if
the person remains inactive during the recovery period. Legumes,
fructose and milk products should be avoided during the recovery
period when the requirement is for rapidly replenishing glycogen
reserves because of their slow rate of intestinal absorption. |
