The problem with high intensity exercise

If you engage in any form of sport, vigorous exercise, weight or high intensity training, then this message is for you. For the purpose of this post, I’ll refer to you as an athlete. After all, Nike says that an athlete is “anyone with a body”.

Many athletes, while aware of some of the science behind biomechanical and neuromuscular aspects of exercise, and know just enough about macronutrients to not get themselves into trouble, most are totally unaware of the effects of exercise on the systems in the body that are highly dependent on micronutrients. One startling example is how many young athletes are dropping like flies due to mineral loss through extreme sweating during intense physical activity. In fact, SCDs (sudden cardiac deaths) are the most common non-traumatic cause of death among college athletes representing about 75% of fatalities in college student-athletes during sport and exercise! I just wrote a blog about this and mentioned the following case that I reported in my Magnesium Miracle book.

Years ago, the coach of a Florida high school football team was concerned about his players’ frequent complaints of leg cramps, so he gave them a calcium supplement on a very hot day before a rigorous game. Early in the second half, eleven players became disoriented and had difficulty walking. Their speech was slurred, they complained of muscle spasms, and they were breathing very deeply. Within an hour, eight of the boys collapsed into full-blown seizures; two had repeated seizures. Those having the worst symptoms had been playing the hardest. Thirteen more players reported headaches, blurred vision, muscle twitching, nausea, and weakness.

Eventually all the boys recovered, but what happened to create such a frightening scene in this group of healthy young men? Consider the facts. Those that were affected had all eaten a pre-game magnesium-deficient fast-food meal consisting mainly of sodas (high in phosphoric acid), carbohydrates, and fats. With the increased magnesium loss from excessive sweating plus the calcium supplement, their magnesium stores had been driven dangerously low.

Don’t think mineral depletion during intense physical activity is real? Just look to the example of US soldiers in Iraq whose shirts became stiff and found clumps of salt in their pockets from working in 125F heat. This is a tangible example of how our bodies lose minerals during intense physical activity. Although athletes would be crazy to work out in that kind of heat, intense training can put the body under the same kind of stress.

When you add to that the fact that many people who consider themselves serious about fitness tend to be on restrictive diets like Paleo and vegetarian diets that further deplete minerals, you have a recipe for putting the body into a dangerously depleted state where injury and disease can easily occur.

Whether you are a weekend warrior or a serious athlete, whether you “go till you blow” or you are trying to go beyond the “bonk”, you need to realize that intense exercise can deplete your minerals to levels that are dangerous in both the short term and the long term. New workout trends like Crossfit have turned the world of exercise into a highly competitive sport, which has raised the bar of intensity and stress, and thereby, depletion. I’m not trying to knock these new workouts, and it’s great that people are becoming more active. But remember, the expulsion of that much effort comes at a cost, so you must consider how you’ll repay that debt.

The easiest way to “pay it forward” when it comes to your mineral levels is to stay topped up with a high absorption magnesium formula like ReMag. The reason the absorption matters for much with magnesium is that most forms of magnesium, when not fully absorbed, cause a laxative effect–something you son’t want to deal with in the middle of a squat set on the power rack!


Dr. Carolyn Dean