Experience From - Karl King, Jim Kirby, John Davis, Ray Zirblis, Sarah Tynes, Ray Zirblis#2,
Glucose is the simplest sugar of all. When other foods are rated for glycemic index, they are rated relative to glucose. I.E. the glycemic index of glucose is 100%.
That can be good or bad depending on your needs. If your blood sugar is really low and you need a quick boost, nothing works faster than glucose. On the other hand, if you chow down on a lot of glucose, you can get a significant insulin pulse that will drag down your blood sugar after the glucose is processed.
It is not desirable to have high insulin levels during an ultra as it can interfere with fat burning.
So, the only good way to use glucose for much of your carbo calories is take small amounts frequently.
The ideal way to fuel yourself during a run is to take in small amounts of carbo on a regular basis so that your rate of intake matches the rate your muscles use the carbo. Then you don't get any insulin pulses, and you don't run into low blood sugar. My preference is to use a sports drink based on maltodextrin ( a lower G.I. than glucose ) and drink a couple times per mile or more. I'll carry a gel pack so that I've got something in reserve if my blood sugar seems to be lagging. The glucose tablets would serve the same purpose, but I like the chocolate flavored gels.
One other good thing about glucose is that it does not have the problems associated with the fructose found in some sodas and sports drinks.
A couple of weeks ago I did the Castle Hot Springs 20 mile training run. This training run is a tune up for the Crown King 50k/50 mile Scramble here in Arizona. I decided to experiment with Glucose Tablets instead of the Gels. I'm here to tell you that these baby's really work. I never bonked and finished feeling fresher than normal. This is what I did, started taking them after the first hour,and every 20-30 minutes then on. I bought the orange flavored from Osco(Sav-on) brand that come in a handy plastic cylinder shape container. Besides tasting good,easy to carry, they seem to really work for me. Just thought I would share this with the ultra tribe.
Just a short comment on the effect of these tabs: they really give you a blood sugar spike. That means both a quick way up and a big way down. Your comments indicate that you were probably running on a low sugar level in your previous runs. The problem I noticed was that if you goofed and took one a little too late, you did go through a rather severe drop in energy and probably had some stomach distress as well.
There is another way to keep your body happy. I wish I had tumbled onto it earlier (Like at WS in 95). It has made a significant difference in how I feel during long runs. It also keeps the requirement for instant recognition of blood sugar variations way down. I use a longer term source of energy. I keep sipping at it whenever I think about it. I do not like to eat as much as drink the energy source. It allows me to breathe through the mouth sooner and follows the precepts of Jim O'Brien as well. He essentially does not eat anything but drinks it all. I tend to temper his direction but acknowledge that his thoughts sure do help in the big picture.
I looked for a cheap (relatively) source of energy in liquid form which I can get anywhere. I looked at the Ensure type drinks since I can tolerate milk type products on the trail. Lots of energy and about 13 miles for a can mixed to half strength. This with Karl Kings salt caps and water or electrolyte replacement drink do excellent things for the bod.
I still carry a gel type and bar if things really go south in the pace and replacement planning (like when an aid station is not there or a drop bag goes and takes a walk).
Try it. you may like the changes.
I carry the glucose tablets, which are a melt-in-your-mouth item, as an emergency 'bonk' food because they are quick and seem not to deteriorate in my kit. Sometimes, when I hit a bad patch, I'll take a couple and feel the sugar right down to my toes. I'd prefer to carry a couple of mini 'Snickers' bars, but they melt and, besides, they wouldn't last till an emergency! Three or four pieces of hard candy or a ratty old stub of stale Power Bar work just as well.
Interesting things, these glucose tablets. I'd never heard of them before last Saturday. I discovered them as I stumbled into the first aid station on loop #3 at MS Trail. I'm reluctant to try anything new during a race, but I was woefully under trained and new I would need a little extra something. Took a few seconds to check out the ingredients (Dextrose, Cellulose, Magnesium Stearate, Citric Acid, Ascorbic Acid, Natural & Artificial flavor, and Color FD&C Yellow 6; 4 grams of Carbs, 17 calories), decided that they were basically harmless, and took a chance. Chewed up a couple and in a few minutes I was ready to run! From then on out I took one at each aid station (2-4.5 miles apart), plus some rock salt that I had with me, and Gatorade (gross!). Finished the 50 miler feeling pretty good, considering :)
But to take the guesswork out of it, I'm ordering Karl's S! Caps tomorrow :)
Ron Christiansen wrote:
"What is the theory behind taking these during a race? I've heard of taking them to help with injuries but not during a race."
I was saying to Chris that I carry glucose tablets, a melt-in-your-mouth item, as emergency energy food because they seem to come on rapidly and don't deteriorate in my kit. I'd prefer Snickers mini bars, but these melt and, besides, would never last till emergencies! 3 or 4 pieces of hard candy or a ratty old stubb of stale Powerbar do just as well for me. I don't have the theoretical knowledge or experience of many folks on this list, but the point is that glucose isn't some magic substance. Any Carbohydrate will do. And if for whatever reason, I haven't kept myself well fueled, a little snack often does the trick.