I do not know whether Col. Raja is a medical doctor. If he is, then he should perhaps have dilated a bit longer to explain the term Hyponatremia. And, if he is not, then.......By the way, the last I had heard of lack of sodium in the blood or in the body was in connection with a disease known as Chikungunya: However, I've consulted Wikipedia and got the following explanation (for those who are interested): quote Hyponatremia (American English) or hyponatraemia (British English) is a reduction in the salt level in the blood. In the vast majority of cases, it is caused by drinking too much water, resulting in an electrolyte disturbance in which the sodium ion concentration in the blood plasma is lower than normal.[1] Lack of sodium alone is very rarely the cause of hyponatremia, although it can promote hyponatremia indirectly and has been associated with MDMA-induced hyponatremia.[2] In particular, sodium loss can lead to a state of volume depletion (loss of blood volume in the body), with volume depletion serving as a signal for the release of ADH (anti-diuretic hormone).[citation needed] As a result of ADH-stimulated water retention (too much water in the body), blood sodium becomes diluted and hyponatremia results. Exercise-associated hyponatremia (EAH), however, is common at marathons and other endurance events.[3] 13% of the athletes who finished the 2002 Boston Marathon were in a hyponatremic state, i.e. their salt levels in their blood had fallen below an acceptable level. Sodium is the dominant extracellular cation (positive ion) and cannot freely cross from the interstitial space into the cell, because charged sodium ions attract up to 25 water molecules around them, creating a large polar structure that is too large to pass through the cell membrane. Its homeostasis (stability of concentration) inside the cell is vital to the normal function of any cell. Normal serum sodium levels are between approximately 135 and 145 mEq/L (135 - 145 mmol/L). Hyponatremia is generally defined as a serum level of less than 135 mEq/L and is considered severe when the serum level is below 125 mEq/L.[4][5] Many conditions including congestive heart failure, liver failure, kidney failure and pneumonia can have an associated hyponatremia. It can also be caused by overhydration from drinking too much water (polydipsia). Symptoms of hyponatremia include nausea and vomiting, headache, confusion, lethargy, fatigue, loss of appetite, restlessness and irritability, muscle weakness, spasms or cramps, seizures, and decreased consciousness or coma.[6] The presence and severity of symptoms are associated with the level of plasma sodium (salt level in the blood), with the lowest levels of plasma sodium associated with the more prominent and serious symptoms (the less the salt the more severe the symptoms). However, emerging data suggest that mild hyponatremia (plasma sodium levels at 131 mEq/L or above) is associated with numerous complications or subtle, presently unrecognized symptoms[7] (e.g., increased falls, altered posture and gait, reduced attention).[8] Neurological (brain) symptoms typically occur with very low levels of plasma sodium (usually
more