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Calcium:
(Ca++, atomic number 20) Female athletes that must maintain low body fat weights, become amenorrheic which can lead to a reduction in bone mineral content. Encourage the RDA (recommended daily allowance for Ca++ in the diet. Reduction in training and a gain in body fat does increase bone density.
Calcium (C++): The RDA of Ca++ decreases the risk of HTN (hypertension). RDA is ~ 800mg/day.
Electrolytes:
Adult electrolyte needs: 500 mg Na+ (sodium) /day, 750 mg Cl-/day, 2000 mg K+(potassium)/day and 800 mg of Ca++/day. Aldosterone regulates Na+, Aldosterone controls the reabsorption of K+
Major intracellular cation is K+ (Potassium, atomic #19)
Major extracellular cation is Na+ (Sodium, atomic #11) (control of mm contraction, conduction of nerve impulse)
Major extracellular anion is Cl-(chlorine, atomic #17)
Cl is not found in free state in nature but as solid or in seawater as sodium chloride (NaCl) and in compounds such as halides, oxides, sulfides, hydrides).
Iron:
Fe++(ferrous), Fe+++(ferric). Functions in hemoglobin (Hgb), myoglobin (Mgb), and the cytochromes (oxidative phosphorylation). Iron deficiency anemia limits aerobic endurance and capacity for work (pt. feels tired and fatigued). Supplement with vitamin C and ferrous sulfate 50- 200 mg (vitamin C will keep iron in the ferrous state)
Test:
With infection serum iron will test low. Bacteria need it to grow, so the body takes it out of circulation. Iron is always bound in the blood (for the same reason, to keep away from unauthorized users) via transferrin (a globulin that binds and transports iron) and is stored as hemosiderin (an iron containing pigment from the hemoglobin of lysed RBC's) until needed for making new hemoglobin and as ferritin, which is stored in the tissues, especially the reticuloendothelial cells of the liver spleen and bone marrow. Related diseases: Iron deficiency anemia, hemosiderosis.
Sports Anemia:
Heavy training can cause a transient anemia with a decreased RBC count, Hgb, Hct. (hematocrit). RBC morphology and color is normal (normocytic/normochromic) and athletic performance does not deteriorate. Possibly due to hemodilution (expanded blood volume) and increased RBC destruction due to intra vascular hemolysis. Supplementation is not necessary unless low serum ferritin is found.
Magnesium:
Magnesium (Mg++): Inhibits vascular smooth muscle contraction. Inverse relationship between intake and blood pressure (BP).
Causes of magnesium Deficiency:
1. Decreased Intake (take more)
- starvation
- prolonged intravenous therapy without Mg++ replacement
- old age
- total parenteral without Mg++
2. Impaired Absorption (taking more does nothing)
- chronic diarrhea
- familial magnesium malabsorption
- fistulas (small bowel, biliary)
- cholestactic liver disease
- malabsorption syndrome
- latative abuse
- GI suction
3. Renal Loss (taking more does nothing)
- uncontrolled DM (ketoacidotic, hyperosmolar)
- Osmotic agents (hyperglycemia, alcohol, mannitol)
- diuretic phase of acute tubular necrosis
- intestinal nephritis
- cyclosporine
- postobstructive diuresis
- glomerulonephritis
- renal tubular acidosis
4. Endocrine
- DM
- hyperparathyroidism (and other causes of hypercalcemia)
- Vitamin D therapy and overdose
- Hyperthyroidism
- Primary hyperaldosteronism
- catecholamine excess
Signs and Symptoms of Hypomagnesemia:
Neuromuscular: muscle weakness, twitching, cramps, tetany, convulsions, paresthesias, mental status changes (confusion, agitation, delirium, coma, depression).
Cardiac: arrhythmias (PVC, atrial fibrillation), ST and T wave changes, prolongation of P-R, QRS and Q-T intervals, coronary artery spasm, increased size of myocardial infarcts.
Metabolic: refractory hypokalemia, insulin resistance, hypertension, hypocalcemia
Neonates: weakness, apnea, high pitched cry, convulsions, jitteriness
Potassium (K+): dietary K+ and blood pressure (BP) are inversely related. Increased K+ intake is associated with decreased BP. Normal ratio in diet to Na+ is 1:1 (Vegetarians normally have increased levels of K+). Clinical trials with K+ had mixed results. Sources of K+ are potatoes, bananas, fruits and other vegetables.