Dehydration through reduced fluid intake or strenuous exercise without adequate fluid replacement increases the risk of kidney stones.
[quote]WHAT IS A KIDNEY STONE? DOES DEHYDRATION CAUSE KIDNEY STONES?
Painter : Kidney stones . . . are crystalline structures that typically contain phosphate or calcium oxalate as the sole or major component. There is no single explanation of the cause and development of stones. In all probability, stones result from the interaction of multiple factors, many of which are as yet unknown. . . .
Mahan : Kidney stones may form in the kidney, in the ureter draining the urine from the kidney, or in the bladder in susceptible individuals. This usually occurs secondary to a urinary tract infection or in individuals who have high urinary calcium excretion, a condition that is most commonly inherited as a predisposition in some families or seen in relation to excessive calcium and/or vitamin D intake.
The most likely candidates for a kidney stone are people with a family history of calcium, oxalate or uric acid stones. Less common, high urinary oxalate excretion, as seen with diets high in oxalate or from excessive vitamin C intake, or high uric acid excretion, as seen in some families related to high protein intake, may lead to stone formation.
Eichner : Men are more likely to form stones than women because men have more calcium and uric acid in their urine, and because men are more likely to work in the heat and become dehydrated. It is dehydration, not exercise per se that increases the risk of stone formation.
Because most stones contain calcium, doctors have long told stone victims to cut calcium by avoiding dairy products. This advice may fall out of favor. A recent study finds that men who eat the most calcium have the lowest risk of stones. Why? Because calcium binds oxalate in the gut, so it passes in the stool and does not enter the body. Sodium per se is not a key risk for renal stones, yet cutting sodium can lower the risk of stones in susceptible persons. This is because sodium and calcium seem to compete for absorption by renal tubules. So the less sodium you eat, the less calcium stays in the urine.
Mahan : Nevertheless, sodium-induced calcium stones in susceptible individuals probably occur as a result of chronic exposure to sodium. Very prolonged intake of excess sodium would be required to develop the high urine sodium excretion that apparently contributes to this condition.
Painter : Epidemiologically, it is shown that the incidence of stone disease is highest at 30-50 years of age, with a higher incidence in whites vs. blacks. The highest incidence occurs during the months of July, August, and September, presumably related to dehydration, which is more common during these times. Other observations indicate that sedentary individuals are more susceptible, as are those with professional or managerial occupations.
To expand on Dr. Eichner’s comment on exercise, the dehydration resulting from exercise increases the concentration of calcium and oxalate in the urine. . . . .
Eichner : The
most critical tip to preventing stones is to quaff fluids - two or more liters per day - to keep the urine dilute
. Other dietary tips include eating more potassium (which somehow lowers urinary calcium excretion), cutting oxalate-rich foods (such as tea, chocolate, and peanuts), avoiding large doses of vitamin C (in the urine, vitamin C turns partly into oxalate), and reducing animal protein in the diet.[/quote]
In summary, exercise does not in itself increase the risk of recurring kidney stones, but rather dehydration. AND, whether you exercise or NOT if you have a history of stones you need to DRINK DRINK DRINK (not beer either). And, then reduce your sodium intake as well as the other dietary suggestions in the quote. Hope this helps.
Bodo