Glycogen, Glucose and sugars for Race energy

So, in my last post I mentioned that I was using pure glucose I purchased at the pharmacy.  I know about these products because my ex was diabetic.  Diabetics often need a fast recovery when their glucose (blood sugar) declines because their bodies do not have working internal governor systems for blood sugar.

For non scientific types there is a lot of hype out there about sugars.  Advertisers want us all to believe that fructose is equal to sucrose.  Unfortunately the chemistry doesn't equate.  Digestion and absorption of fructose is different than sucrose and these are both different than glucose.

Let me say it this way:  GLUCOSE DOES NOT REQUIRE DIGESTION.  Glucose is the sugar the body uses in the brain functions and in muscles.  When you are in a race, fast acting sugar to your blood stream that by-passes the need for digestion is extremely helpful.

When you do extreme exercise, your digestive system tends to shut down.  Blood flow needed for effective digestion is redirected to the muscles to keep them running.  So ingesting food during the race is somewhat ineffective and can create disgestive stress.  GUs are often comprised of Dextrose which is considered equal to Glucose (some chemistry here:  there are two types of dextrose due to chemical structure.) but they are not completely made of dextrose.  Other components must be digested.  Thus you take in a good liquid product that has some glucose in it and your body responds.
However, I find that some GU flavors and some ingredients sometimes cause me to feel nauseous and at times I just don't feel capable of keeping even those flavors I like down.  I have begun to use both GUs and glucose on my races.  I found that glucose in liguid, gel, and tablet form was much easier to get down and appeared to keep my energy levels higher longer.

Although I no longer body build, I find that body builders have been experimenting with supplements such as glucose and amino acids for many years longer than triathletes and sometimes their sites have some useful insights.  Here is one site I like and a few quotes from it:

the-benefits-of-post-workout-carbohydrates

Fructose is a form of sugar that the body doesn't really use well. Because of its structure, it can't be directly turned into muscle glycogen like glucose can. When you consume fructose—fruit or high-fructose corn syrup—it's not absorbed immediately into the bloodstream like glucose/dextrose. Instead, the majority of it must travel to the liver, where it can be converted into glucose and stored as glycogen to be released as glucose when the liver deems it necessary to maintain blood glucose levels.

My note:  Fructose is found in virtually all carbonated sodas.  It is also a major component of candy.  Sucrose, digested in a similar fashion to fructose but more slowly, is found in candy, sweet breads and manfactured solid food.  In large quantities, sucrose is much harder to handle than HFCS (High fructose corn syrup) because it tends to clump and is hydroscopic which means it absorbs water.  HFCS is liquid and can be pumped making it much easier to transport and move during production.  It's also cheaper.  

DEXTROSE THE BEST POST-WORKOUT CARB SOURCE

Consuming pure glucose—also called dextrose—after a workout means the body doesn't need to digest it. Because post-workout glucose can be absorbed into the bloodstream almost as quickly as it's ingested, it gets to your spent muscles as rapidly as possible, resulting in the quickest and most complete replenishment of muscle glycogen. This will keep muscles stocked with ample glycogen for your next workout and pull water into your muscle cells, maximizing your muscle size.

You should also keep your GU or other products in your mouth for as long as you can tolerate.  Suck small amounts during your race and swish it around to get the maximum effect of salivary digestion.  Check out this diagram from another site. -introduction-to-nutrition/s08-02-digestion-and-absorption-of-ca.html

Salivary glands secrete salivary amylase, which begins the chemical breakdown of carbohydrates by breaking the bonds between monomeric sugar units.

Monomeric sugar units pass through the digestive system and require less "processing" than polymeric ones.  So help your body by using this "pre-digestion" process as much as you can during your race.  

And here is another diagram from the same site above: 

Carbohydrate digestion begins in the mouth and is most extensive in the small intestine. The resultant monosaccharides are absorbed into the bloodstream and transported to the liver.

Note that carbohydrates must move through to the small intestine and then to the liver.  This is why there is a long delay in getting nutrition to your muscles.  If you are not proactive in getting nutrition into your body, you can end up with a deficit that is very hard to make up for during the race since digestion slows further during exercise.

Thus the glucose can overcome that delay and provide immediate boosts to your system while you wait for the more complex carbohydrates to be digested.
You might experiment with some of the glucose products found in the Diabetes support aisle of your pharmacy to see how they might help you.  I love the tablets that taste like sweet tarts.  There are also liquid products in gel or more fluid form and a variety of flavors.
Here is a site that offers glucose gels, just one of the many products out there.  The chart below is from their site comparing the effects of various sources of sugar.
glucose-gels




I hope this has helped you to understand what is happening to your blood sugar and how to manage it a bit better on your race....And why I am strongly preferring pure glucose to other items.
Of course there is a caveat.  Many GUs are formulated for athletes and contain electrolytes as well.  I get my electrolytes in another form.  I'll talk more about that in another post.