Most of us have been there – we’re having a great race – we feel phenomenal – all the training has paid off– then all of sudden the leg cramps begin. First it’s just a tingle, something we can ignore but then it escalates and feels as if a bulldog has clamped its jowls down on your quadriceps. There’s no denying it now: you are either dehydrated, or electrolyte depleted, or both. And so the game of catch-up ensues – first you slug down water, then a sports drink, then the two remaining gels in your pocket. Your run slows to walk, and then to a limp, now you are slumped over massaging your screaming muscles. Your competition flies by you – “Hey, are you doing ok? Need anything?”.
Later that night, after you’ve congratulated your friend who took your spot on the podium, you review your pre-race and race nutrition. It all seemed go as planned: You hydrated that morning before the start, consumed your usual pre-race meal at the prescribed time, set your heart rate monitor to beep every 20 minutes and you drank a pre-determined amount of your favorite sports drink and slurped down a gel. So what happened, what’s missing? It might just be magnesium.
Magnesium? Isn’t that something mined from the ground? It’s also a mineral found in the human body that regulates so many biochemical reactions it causes the head spin. Over 300 enzymes systems in your body are dependent on an adequate level of magnesium. The most important of these govern athletic performance and include the function of muscles and nerves, blood sugar control via glycolysis, and all-important cardiac function. In other words, without magnesium, your muscles won’t contract, your heart might not beat properly, and your blood sugar level will drop into the basement. The chemical that tells your hemoglobin to release oxygen to your working muscles, heart and brain– 2,3 DPG – guess what, it’s synthesis is dependent on magnesium. It doesn’t matter how high your hemoglobin is if you can’t effectively access the oxygen that it is designed to deliver.
A few athletes have hired me to specifically address problems they experience with “bonking” and cramping during races. The common denominator for most them has been a lack of magnesium. And I’ve personally experienced the same phenomenon. Our body stores most of our magnesium in our bones and soft tissues and only 1% is readily available in the serum for immediate use. Magnesium is lost in sweat in urine and these losses are increased by up to 20% in an exercising athlete. As people age magnesium is less efficiently absorbed from the gut and is excreted more readily by the kidneys. The recommended daily allowance (RDA) for magnesium ranges from an average of 340mg for adult females and 415mg for adult males. So what are the main dietary sources of magnesium? The top five are almonds, spinach, cashews, peanuts, and soymilk. The National Institutes of Health provides an extensive list of magnesium containing foods on their website.
Finding sports nutrition products that contain magnesium is no easy task. Over the years numerous manufacturers have added and removed magnesium from their products. The landscape of electrolyte ingredients in nutritional products designed for athletes is ever changing. Do your research. Make sure you are regularly reading the ingredients on your favorite supplements. One easy strategy to ensure adequate blood levels of magnesium is to choose a sports drink with magnesium and drink 2 to 3 ounces every 15 to 20 minutes. For events lasting over 90 minutes it’s wise to supplement with a gel product that contains magnesium approximately once every hour. If your athletic venue is going to be hot your will lose more magnesium via sweating, so plan accordingly. Electrolyte capsules and dissolvable tablets that contain magnesium can be crucial to performance for longer races on hot days. The same advice can be applied to training as well. Magnesium will boost performance during training (thereby making it more effective); it also aids in recovery. Consider magnesium your new secret weapon in the electrolyte arsenal!