- - Magnesium: The Orphan Electrolyte

Magnesium: The Orphan Electrolyte

 article by Molly Breslin

Most of us have been there — we’re having a great race, we feel phenomenal, all the training has paid off, and then all of a 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 a 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 to 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 to spin. Over 300 enzyme 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, its 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 percent is readily available in the serum for immediate use. Magnesium is lost in sweat and urine and these losses are increased by up to 20 percent 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 soy milk. The National Institutes of Health provides an extensive list of magnesium containing foods on its 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 you 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!



Jackson Hole, Wyoming is where I work and play. My life has been spent working in a variety of professions and locations, from framing houses in Alaska to volunteering in medical clinics in the Himalaya and Africa. Besides coaching, I am a practicing nurse anesthetist who has worked in over 45 hospitals across the country, from New Jersey to Hawaii. I studied economics and business administration at Ursinus College and biology at Temple University. After working in sales management and marketing in the greater New York/Philadelphia area, I returned to nursing school at Pennsylvania State University and spent the next eight years working in critical care neonatology and pediatrics at The Children’s Hospital of Philadelphia. During this time I did my biomedical graduate work at University of Pennsylvania and then completed a Masters of Science in Anesthesiology at Saint Joseph’s University and clinical anesthesia training with the University of Pennsylvania Health System.

I’ve earned a professional certification in Sports Nutrition and Nutrition for Optimal Health and Wellness from San Diego State University. I am a Level I USA Triathlon Coach and a certified Health and Wellness Coach for Wellcoaches (an affiliate of the American College of Sports Medicine and Harvard University School of Medicine). Besides coaching individual athletes, I have coached a women’s developmental running group through Runner’s World in Emmaus/Allentown, Pennsylvania. I also maintain certifications in TRX Suspension Training and Schwinn Indoor Cycling.

Adult-onset asthma introduced me to exercise as a way to control my breathing difficulties. Very quickly I found myself hooked on triathlon and progressed from a wheezing, almost dead-last finish at my very first race to frequenting the steps of the podium and earning the Wyoming State Triathlon Champion title as well as a national recognition as one of the Top 50 Amateur Triathletes in the Best of the US Triathlon competition. Realization that I could not have accomplished these goals without good coaching, as well as my love of teaching and mentoring led me into a career of coaching. I continue to practice in the medical profession part-time and continue to race, affording me the experience and the wisdom to successfully coach busy professionals as well as coach athletes with medical challenges.


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