Question

Sodium depletion occurs in excessive sweating, and cannot be corrected by drinking water alone. When uncorrected it may lead to,
A) Swelling of ankles
B) Increase of urea in blood
C) Muscle cramps , loss of energy, fatigue and faintness
D) Renal failure

Answer 1

Sodium is an electrolyte and mineral. It helps to maintain the water and electrolyte balance of the body. Sodium is also imperative in the working of nerves and muscles. Most of the sodium in the body is present in blood and lymph fluid.

Complete answer:
Body fluid volume and electrolyte concentration are usually maintained in very constricted limits in spite of wide variations in dietary intake, metabolic activity, and environmental stresses. Homeostasis of body fluids is conserved primarily by the kidneys.
Water and sodium balance are closely mutually dependent. Total body water is about 60% of body weight in men that is in the range from about 50% in obese people to 70% in lean people, and about 50% in women. Almost two thirds of total body water is in the intracellular compartment that is intracellular fluid, or ICF. The other one third is extracellular, extracellular fluid, or ECF. In general about 25% of the ECF is in the intravascular compartment. The other 75% is interstitial fluid.
The average daily fluid intake of an individual is about 2.5 L. The amount required to replace losses from the urine and other sources is about 1 to 1.5 L per day in healthy adults. On the other hand, on a short-term basis, an average young adult with normal kidney function may drink as slight as 200 mL of water each day to excrete the nitrogenous and other wastes produced by cellular metabolism. Additional is needed in people with any loss of renal concentrating capacity.
Sodium gets lost through sweat. If it is not corrected the following symptoms may occur.

Nausea and vomiting
Headache
Confusion
Loss of energy, drowsiness and fatigue
Restlessness and irritability
Muscle weakness, spasms or cramps
Seizures
Coma

Hence the correct answer is option (C) muscle cramps, loss of energy fatigue and faintness.
Note: Hyponatremia is a condition which occurs when the concentration of sodium in one’s blood is abnormally low. Sodium is an electrolyte and it helps to regulate the amount of water that's in and around the cell.