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Fuelstrips tell you when and how much to fuel for your sports

Take two if you are orange!
Take two if you are orange!



Anyone who trains for long distance events understands that they need to know when to replace electrolytes and how much they need to take in to stay balanced. Electrolytes are substances that conduct electricity. In our cells the electrolytes are sodium, potassium, magnesium, chloride, and calcium among others. The goal is to keep electrolytes in balance, so that the cells in your nerves, heart and muscles can carry electrical charges across themselves and to other cells. Exercise, which depletes water and electrolytes, can change the balance as can drinking excessive amounts of water.

What's in your sweat?

Athletes lose sodium and potassium in their sweat. If you lose enough, along with the transfer agent, water, you can upset the balance in your body. As you exercise the percentage of water output via sweat rises above that of urine, so your water intake should increase without the need to frequent the porta potty. Go back to science class and think about acids and bases. If your balance of electrolytes changes (some are positive and some are negative) the pH in your body changes. Neutral is 7.4 below 7 and above 7.8 are lethal. Remember the pH strip you used in science class to test for acids and bases. The strips turn colors based on the pH of the substance tested. Stay tuned you can create your own science experiments while you work out.

Some of the major positive ions (cations) are
Na+ sodium
K+ potassium
Ca2+ calcium
Mg2+ magnesium
Some of the major negative ions (anions) are
HCO3- bicorbonate
Cl- chloride
HPO4 2- hydrogen phosphate
SO4 2- sulfate
The main extracellular fluid mover is Na+. The main intracellular fluid mover is K+.

Ammonia is NH3. Why is this important? Nitrogen is an amino acid which your body uses for energy every day. Amino acids are the building blocks of protein. Our bodies are constantly breaking down muscle and building it up on an hourly basis. As we age we need to focus on exercise that builds muscle since the break down process occurs faster.

When you start to exercise your body will first use fat for fuel. The average person has between 60,000 and 80,000 calories of fat stored. That is enough calories to fuel ten back to back Ironman races. That is provided that you stay in your fat burning zone. The fat burning zone is where your heart rate is low and you are using oxygen to convert the fat to fuel.

As you increase your effort and your heart rate rises the mix of fuel changes. Your body cannot convert fat fast enough so it looks to your glucose stores. The average person has about 2,000 calories of readily available glucose. Your brain can only use glucose for fuel, so it will take what is needs before allowing other organs and your muscles to use those stores. If you just raise your heart rate enough to dip into the stores and then lower it back to fat burning zone you can go further. If you continue to push harder and let your heart rate rise you will at some point burn through the available glucose.

Once those glycogen stores are depleted (and not replaced) the body will use amino acids for energy. It does this by stripping the nitrogen atom off the molecule and converting what is left behind into glucose. Your body usually processes nitrogen in your kidneys and forms urea. But if your kidneys can’t handle the volume of nitrogen it will be excreted as ammonia in your sweat. Water is the transport vehicle in either case.

To keep your body from breaking down amino acids you need to keep glucose readily available to your muscles. The question then remains how much. Manufacturers will tell you to take one package/serving every 15-30 minutes (with water). This might be right for one person but provide an excess for someone else. You can certainly play around with taking different amounts of product in different concentrations to see what works best for you. You can also use a new product called Fuelstrip to help gauge what you need and when. Here is where the pH strip idea comes into play.

Fuelstrip are colored strips you use to test your sweat while working out. From the company’s website “Fuelstrip has developed a patented technology that is able to detect these metabolites in your sweat and provide a gauge for when your glycogen fuel tanks are becoming depleted and you begin to break down muscle. As your glycogen reserve tanks are depleted from full to empty, the Fuelstrips react to form a series of colors that approximate a full tank (orange), 3/4 tank (yellow), 1/2 tank (green), 1/4 tank (blue). The periodic testing of your sweat will allow you to refuel to your body’s exact needs at the moment.”

Since everyone’s sweat rate is different you will need to try the strips out to see how often you need to ‘test’. The company suggests every 15 minutes, but if you are a fat burner you may still be orange after an hour. The test couldn’t be easier. Swipe sweat off your head onto the strip, wait 15-30 seconds, and watch the color change. Caveat: be prepared to read the results. If you wait the test area will dry and return to a yellow color.

I tested the strips on myself after a 60 minute spin class. I wore my heart rate monitor, so I know I stayed within my aerobic zone. I was unable to change the color on the strip. Even after an hour and a half of an aerobic ride I still did not change the strip color. I then tested after an hour and a half with some bumps up to the ceiling and my strip began to move to a yellow. You are supposed to test periodically throughout your workout.

I tested with some heavy sweaters in my indoor power cycling class. For test purposes I did not test as we went, but wanted to see how much the strip might change if they just fueled as usual. I had them for an hour and a half with some breathless segments as well as long holds at FTP (strong effort but should be aerobic). Philip was probably the lowest sweat rate. He turned the strip a solid yellow drinking primarily water during the indoor ride. After looking at his heart rate it had not ever gone too high. Jim also tested for me. He has been working on building his aerobic base, so knew that he had crossed the threshold a few times, but never for more than a minute. His strip went to green and he drank one water bottle of his favorite electrolyte mix which does have some glucose. Juan had been under fueled for the previous workout. This time he had a Gatorade and a tomato juice prior to the class start. Even with that fuel prior and electrolytes during he was still green moving into blue after an hour and a half. Since testing with the strips he has focused more on both electrolytes and glucose during even 90 minute rides. The group also tested out the Fuelchews and all gave a thumbs up. My son agreed with me that they were pretty sweet (when not working out). The have a bit of a gritty (sugary) texture, but the flavor is good.

The chews are made with tapioca syrup, pectin, citric acid, natural flavor, color added, potassium citrate, trimagnesium citrate, tricalcium citrate, fractionated coconut oil, and carnauba wax. The chews are gluten free and dairy free. 1 piece is a serving and contains 30 calories with 65mg sodium, 5mg potassium, and 8g carbs (5g sugar).

Another group had similar responses when testing during another power cycling session. For some it was a surprise, but as they thought about how they typically felt at the end of a ride it made sense that they might be under estimating their electrolyte needs.

A set of 6 strips is $2.49. Fuelstrip started with Fuelchews at $2.49 per bag. A starter pack has 2 vials of Fuelstrips and 3 bags of Fuelchews. Recently Fuelade was added and coming soon Fuelwater.

Endurance athletes need a combination of electrolytes AND glucose to keep going strong. Some products are pure electrolytes and others pure carbs, while some are a combination. I will definitely be using the Fuelstrips on my long runs as we go outside this spring. While I have a low sweat rate and stay pretty aerobic I do tend to hit the wall in my marathons. I think getting a better understanding of when and exactly how much I need to fuel (without going overboard) will really help. This product might be a real asset to athletes with digestive issues on the run. I also plan to use the strips with my boys at soccer and baseball tournaments to make sure they stay appropriately fueled.

For those who want to make their own products. You can use the strips and make your own drink. Nancy Clark is a sports nutritionist, below is her homemade electrolyte drink recipe

Yield: 1 quart
4 Tbl sugar
1/4 tsp salt
1/4 c boiling water
1/4 c orange juice (not concentrate) or 2 Tbl lemon juice
3 3/4 c cold water
dissolve sugar,salt in hot water, add juice & cold water, chill
50Cal, 12gCHO, 110mgNa, 30mgK per cup

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