"I played soccer all my life, including as an adult for over 10 years at a high competitive level, approximately 30 matches a year, practices, etc."
"I always felt, the day after a match, like I had been beaten with a stick over every square inch of my body.'
Soccer, marathons and competitive bicycle riding may push the envelope a little too much for those who are really into it and are conditioned to perform at peak level several times a week.
Our youngest son is addicted to bicycle riding. He does over 10,000 miles per year while working 40 to 60 hours per week. He has basically zero body fat and his resting and active pulse rates are amazing low.
However, we have seen him several times reach what he calls his peak condition and get whacked a little later somehow by his immune system. It takes him a couple of months to recover. Then about a year later there is another attack by his body on him.
The last one scared him with a GI bleed, some anemia and feeling miserable for about two months.
There is a fine balance with some of these athletes and some severe problems where their bodies seem to attack them.
Leading theories concern neurotoxicity relating to abnormalities of calcium and amino acids (especially glutamate) essential to neurotransmission. Excessive entry of these compounds into the neurons damages cell metabolism, resulting in pathologic changes. Neuronal damage could similarly result from oxidative processes that produce hydroxyl radicals. Clinical trials of medications that attempt to reverse these processes are under way. Other hypothetic causes of ALS include neurotoxicity from various metals, chemicals or foods,12 and, conversely, deficiency of neurotrophic agents (poorly understood proteins that enhance neuronal maintenance and growth).4,
An intriguing theory that brings together several factors holds that ALS develops when vulnerable persons are exposed to a neurotoxin at times of strenuous physical activity.14 For example, bursts of maximal muscle strength in athletes could create conditions that would deliver such a toxin to the anterior horn cells.