OVER DRINKING OF WATER CAUSES HYPONATREMIA.
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. 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. 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). 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. 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.
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. 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 (e.g., increased falls, altered posture and gait, reduced attention).
Neurological (brain) symptoms typically occur with very low levels of plasma sodium (usually <115 mEq/L). When sodium levels in the blood become excessively low, excess water enters the brain cells and the cells swell. This is called hyponatremic encephalopathy. This is very dangerous because the soft brain is confined by the rigid skull. As the brain expands tentorial herniation can occur which is a squeezing of the brain across the internal structures of the skull.
This can lead to headache, nausea, vomiting and confusion, seizures, brain stem compression and respiratory arrest (stopping breathing), and non-cardiogenic pulmonary edema (fluid in the lungs). This can be fatal if not treated promptly.
The severity of symptoms depends on how fast and how severe the drop in blood salt level. A gradual drop, even to very low levels, may be tolerated well if it occurs over several days or weeks, because of neuronal adaptation. The presence of underlying neurological disease, like a seizure disorder, or non-neurological metabolic abnormalities, also affects the severity of neurologic symptoms.
While on the subject of quantity of water needed to be consumed daily, I wish to reproduce an article that appeared in The Economic Times some time ago. I quote :
" How much water do we really need? ' Drink at least eight glasses of water a day' is an adage some obsessively follow. Judging by the people sipping on water bottles at every street corner, but the need for so much water may be a myth. Caffeinated drinks don't count because they dehydrate? Probably wrong, too. So says a scientist who undertook an exhaustive hunt for evidence backing all this water advice and came up mostly, well, dry. Now the group that sets the nation's nutrition standards is studying the issue, too, to see if it's time to declare a daily fluid level needed for good health and how much leaves you water logged. Till then, ' obey your thirst' is good advice, says Dr. Heinz Valtin, professor emeritus at Dartmouth Medical School. In fact, people absorbing much water from the food they eat. Fruits and vegetables are 80 - 90 % water; meats contain a fair amount; even dry bread and cheese are 35% water, says Rolls. ----AP "
Different research papers appearing far and in between confuse the common man, each paper quoting data to prove their point. How does a common man decide what is right and what is wrong? A laborer working in hot sum might be needing a lot more potable pure water (which he cannot afford), and a man spending most of his time in the cool comfort of an AC would be drinking eight glasses of water daily which his system cannot absorb probably ! Is he not putting a lot more pressure on his kidneys to filter eight glasses of extra water which might not be needed for the body? This doubt has always hunted me and I could not find the right convincing statement.
Can the knowledgeable suggest to me what is the test to find out who needs how much water to be consumed daily? more