The Effect of a Marathon Run on Plasma and Urine Mineral and Metal Concentrations

Abstract

Serum and urinary magnesium concentrations decrease during endurance running, consistent with the possibility of magnesium deficiency. This may be related to increased demand in skeletal muscle. Serum iron concentration increases, possibly related to tissue injury. The exact etiology for these observations, as well as their clinical significance, requires further investigation.

Extracellular Zn2+ Activates Epithelial Na+ Channels by Eliminating Na+ Self-inhibition

“…These observations, together with our data indicating that external Zn 2ϩ at concentrations in the low micromolar range enhances Na ϩ influx via ENaC by relieving Na ϩ self-inhibition, suggest that extracellular Zn 2ϩ may be a physiological regulator of ENaC. Urinary Zn 2ϩ concentrations of ϳ5 M have been reported in humans (29,30), and given the low concentration of proteins and amino acids in urine that could potentially bind Zn 2ϩ , free urinary Zn 2ϩ concentrations likely reach levels that affect ENaC activity. Because increases in rates of urinary Zn 2ϩ excretion may be associated with increases in ENaC activity in collecting ducts by relieving Na ϩ self-inhibition, we propose that increases in the urinary concentration of Zn 2ϩ may increase the risk of developing salt-sensitive hypertension.…”

Timing of post-exercise carbohydrate ingestion: influence on IL-6 and hepcidin responses

“…In addition, the elevations in serum ferritin may result from exercise-induced haemolysis (Weight et al 1991) leading to the leakage of tissue ferritin into the circulation. Significant increases in serum iron were also reported post-exercise in both DCHO and ECHO trials, suggesting an exercise-induced haemolytic reaction, characterised by increases in free haemoglobin (Hb), serum haptoglobin (Hp) and serum iron (Buchman et al 1998;Peeling et al 2009b), occurred in response to the interval running. After exercise increases in serum iron, that is bound to the circulating protein transferrin, may have a supplementary effect on the hepcidin response, as a result of the homeostatic regulation of iron, whereby increases in serum transferrin bound iron levels result in the up-regulation of hepcidin (Kroot et al 2011).…”

Cumulative effects of consecutive running sessions on hemolysis, inflammation and hepcidin activity

“…In addition to free Hb and serum Hp, post-exercise increases in serum iron also reflect a hemolytic stimulus (Buchman et al 1998). As previously mentioned, increased iron levels are also involved in the up-regulation of hepcidin activity (Nemeth et al 2004b).…”