No matter how many times I hear how our energy reserves are similar to a car’s fuel tank, it still kind of makes me laugh. But it’s really the perfect way to describe it, however humans are a little bit more complicated. We actually have three different “tanks” from which to get our energy (ATP): glycogen stores (located in the muscle and liver), muscle and fat. The energy that we get from our glycogen stores is readily available and is what our body primarily burns off first, but it burns quickly, usually within two hours of intense activity. Once we’ve tapped out our glycogen stores, our body starts to tap into the other two fuel tanks: muscle and fat.
Some of the more experienced athletes out there (and the genetically lucky) break down fat first, which has a great deal more energy stores than muscle, and is also easier on the gut itself. But unless you are extremely well conditioned, your body begins the very taxing process of pulling ATP from your muscles. This process involves a complicated chain of reactions that creates toxic metabolites in the form of ammonia, which is expelled from your body in your sweat. This process also causes fatigue and diminished performance, especially when combined with dehydration. But because we are all unique and have different levels of glycogen stores, hydration levels, fatigue and even conditioning on any given day, it can be difficult to know how and when to replenish your glycogen stores so you continue to run on your premium fuel during extended, intense periods of activity.
What Fuelstrip tabs do is take the guessing game out of it all by detecting the level of metabolites in your sweat, providing a gauge of when your glycogen fuel tanks are becoming low and you are in danger of falling into that “muscle breakdown” area. The strips, when moistened with your sweat, turn a series of colors that approximate a full glycogen tank (orange), 3/4 tank (yellow), 1/2 tank (green) and 1/4 tank (blue). By seeing these visual cues, you can respond quickly and effectively by consuming the necessary amount of calories (and glucose) that you need to try and stay “in the orange”.
To make things even easier, Fuelstrip has also developed a line of energy chews which can be ingested based on your test strip color (yellow equals one chew, green equals two chews, etc.). They are your basic energy chew, but they taste good, and work well if you’d like to keep your nutrition plan as simple as possible.
Testing it out
For a long time, I stuck very closely to the printed ingestion guidelines on the package of energy gel I consumed during long rides and runs. Often, this naïve outlook of mine ended with me either bonking halfway through my run, or worse, sitting on the side of the road with GI issues after ingesting more glucose than my gut could process. I’ve learned a lot more about my own nutrition needs since then, so when I set out on a 15 mile run with my vial of Fuelstrip tabs, I was curious just what I might learn about how long it takes me to deplete my tank. Fuelstrip founder, emergency room physician Dr. Boaz Rosenblat, told me that as a well conditioned triathlete, it would take much longer for my body to make the switch from using my glycogen stores to my muscle, as I would most likely burn fat before muscle and therefore sweat out much less ammonia.
I placed the vial in my Fuelbelt and began my run, setting my GPS to beep every 20 minutes so that I could test my sweat. It was a rather warm day, and I had also eaten a decent-sized meal the night before, all factors that would no doubt have an effect on my glycogen levels and sweat rate.
After 40 minutes and two strip tests, my stick was still orange, and at the hour mark it seemed only slighty lighter in color. I was drinking an electrolyte mixture roughly every 15 minutes so I felt I was staying relatively hydrated despite my heavy perspiration in the sunny conditions. At the 1:20 mark of the run, my stick turned yellow, and so I took in approximately 100 calories of nutrition and pushed onward. At the two-hour mark, with my run nearly finished, my stick was back to orange and I was feeling pretty good. Using the strips was fairly easy (you just hold them against a sweaty area such as your forehead or chest), even while running, but if you feel silly holding a strip to your forehead while running down the street, I suggest waiting until you hit a stoplight or duck in to use the restroom.
What I gleaned from this experiment with Fuelstrip is that in those same weather conditions, and with good nutrition the night before, my body would benefit from calorie intake at about the 80-minute mark during a long run. It’s important to note that this might not be the case during different weather, or if any internal factors change, but then again that’s where having the strips can be beneficial. Instead of using nutritional guidelines listed on packages, which can be incredibly vague, Fuelstrip tabs give the consumer their own litmus test in real time to determine what intake will optimize their peformance on that day. Fuelstrip tabs are even more useful for athletes in the building phase of a training program, because not only can they use them to determine their nutritional needs, but they can also see over time how those change based on their increasing fitness levels.