Prolonged exercise is defined as exercise lasting for more than one hour. Many bodybuilders preparing for contests train several hours a day and thus are subject to adverse and possibly dangerous changes in body chemistry. These changes usually involve the status of essential minerals. The body seeks to maintain such minerals at a steady state, and if that steady state is disturbed, problems can occur.
The symptoms can occur in as little as 60 to 90 minutes. That’s particularly true if you haven’t been eating sufficient nutrients or, in some cases, doing something as seemingly innocuous as drinking plenty of water.
v Extended exercise may result in low magnesium levels, especially during hot weather. That, in turn, leads to weakness and muscle cramps. Bodybuilders who’ve used pharmaceutical diuretics often experience painful muscle cramps. Diuretics are used to promote the loss of excess water, which can obscure muscular definition, but the drugs also promote loss of electrolytes, or minerals needed for muscle and nerve function, including magnesium.
In a worst-case scenario that luckily rarely occurs, a low magnesium level leads to adverse cardiac effects. These can include formation of a blood clot in a coronary artery or a spasm of that same artery. Either will result in a myocardial infarction, or heart attack. Dogs deprived of magnesium often die of a sudden heart attack.
Potassium is another essential mineral affected by long exercise sessions. The body usually regulates potassium levels efficiently, since too much or too little can cause serious heart problems. In fact, the first step in stopping a heart for transplant surgery involves injecting it with potassium, which stops a heartbeat like a bullet.
Potassium levels are not likely to be a problem for most bodybuilders unless they are using drugs such as Aldactone, which spares potassium in the body, thus increasing its concentration in the blood. Several prominent bodybuilders have ended up hospitalized because they were unaware of the relationship between potassium-sparing diuretics and potassium-supplement intake.
Most bodybuilders know that sodium is associated with water retention, so they are careful to limit their salt just prior to a contest. But reducing sodium by too much (less than 500 milligrams daily) will likely result in painful muscle cramps. Drinking water helps the body get rid of excess sodium, but when that’s combined with a low-sodium diet, symptoms of too little sodium may appear, particularly during any type of physical exertion.
An extreme example of that occurred at last year’s Boston Marathon, when a 28-year-old female runner died after the race. Friends said later that she appeared well throughout the race and had drunk large amounts of Gatorade, a commercial sports drink, before and during the race. An autopsy of this unfortunate young woman revealed that she died from a swelling in her brain due to a lack of sodium brought about by excessive fluid consumption.