Can your sweat offer clues as to when and how much you need to refuel during a workout? This is the idea behind Fuelstrip. By wiping your sweat as you workout, the Fuelstrips change color to tell you the state of your glycogen stores and when it might be time to top them up.
We all know that eating and drinking during endurance exercise can delay fatigue and enhance our performance. However, it is not always easy to know exactly how much to eat and when. Most people, myself included, either simply refuel when they start to feel tired or eat whenever they get the chance to take a break.
Fuelstrip is trying to make refueling more of an individual science and less of an art with test strips designed to detect the amount of ammonia in your sweat. As you exercise intensely over time, your glycogen stores begin to deplete and your body turns to fat and muscle for energy. Once you reach the point of muscle break down, circulating levels of ammonia increase and are continually excreted in your sweat in larger volumes. The Fuelstrips detect these increasing levels of ammonia, changing colors to visually demonstrate your progressive muscle break down.
Once wiped against the sweat on your forehead, the Fuelstrip will change color from orange to yellow to green and finally blue as your glycogen depletion progresses. Conveniently, the company also sells their own chews and recommends eating a corresponding number of Fuelchews according to your Fuelstrip test results (1-4 chews). I imagine the Fuelstrips will work well with any energy chews or similar food just by comparing carbohydrate amounts and other ingredients.
Given that one vial containing 6 Fuelstrips costs $2.49, you could be spending tons of money per workout if you tested at the recommended 15 minute interval. However, the strips could be interesting to use as a test from time to time to see how your body is adapting to training programs or during endurance events for optimal performance.