Mineral water for sport and living

Question

I live in Czech Republic and the doctor here (for other matters I won't get into) suggested that I start drinking a specific mineral water with the following composition in milligram per liter:

Na       5,06
K        2,58
Ca       35,3
Mg        179
Fe      <0,10
Cl-      3,40
SO42-    14,0
HCO3-    1048
Residual at 180°C 782 mg/l.

Where I come from we only drink mineral water as tap water is generally considered polluted and we've always been told to drink water with low mineral content < 100 mg/l because water high in minerals can build up stones in your kidneys.

This water in particular is very rich in Magnesium and from what I know it's good for sport activities (I run 7km every other day) but I'm afraid that drinking this water could actually do me more harm than good (although in the short term it might help get rid of the problem the doctor prescribed it to me for).

Answer 1

Water's water. As long as it is water and does not contain known poisons like pathogens or heavy metals then you'll be fine.

You don't need much Mg for proper function. The well respected authority on the sceince of running, Dr Tim Noakes, is quoted as saying:

Magnesium is another intracellular ion that, like potassium, is lost in sweat and urine during exercise. But the losses are trivial. There is no published evidence showing that magnesium deficiency is either common amongst the physically active, or that magnesium supplementation can either increase the intracellular magnesium stores, or enhance performance (15). The balance of evidence indicates that although body iron stores may be marginally reduced in some athletes, especially long distance runners, the incidence of true iron deficiency requiring treatment is no higher in the physically-active than in the sedentary population (16,17). Furthermore, the causes of iron deficiency anaemia in the physically active are not different from the causes of the condition present in sedentary persons. There is no indication for the indiscriminate use of iron supplementation by the physically active.

Running 7km every other day is a fairly normal kind of exercise so I would be surprised if such an effort required Mg supplementation.