Some myths go around forever, you think that they belong to the past, that the new generation must be much more clever than to believe some unfounded story as if it was the truth. And yet, by their very nature, myths never go away.
A myth may be defined as “a widely held, but false belief or idea”. And that is exactly what this is about, the widely held false belief that you need to replenish salt, as sodium chloride, when you lose water through perspiration.
Usually the nature of a myth is harmless, well at least most of the old wives tales that go around from time to time are harmless. But some myths are dangerous, and this one is no exception. To take in salt when you are dehydrated is inviting serious problems, such as heat stroke, coma and sudden death.
Let us take it from the beginning. When you perspire, like soldiers, athletes and the most of us do, we perspire to cool down the body. In the process, you will lose some water and depending on the conditions, often a lot of water. If you do not drink water during your activity, you are going to dehydrate.
And here is the myth. Last night, reading from Bill Bryson’s ‘”THE BODY, A Guide for Occupants”, the myth resurfaced again. Bill Bryson in his new book explains “…..together with the water, you lose a lot of salt, and you should also replenish that…..”
OK, so do we now return to the 1970’s when we fed soldiers, rugby players and athletes salt tablets? And the late Prof Nic Strydom from the Chamber of Mines almost had a fist fight on national television with the Army Generals who insisted that this myth is true and the late Professor convinced them to stop this dangerous practice that directly caused the death of a number of soldiers in those years? I thought the myth was laid to rest there and then.
The first important fact to remember is that perspiration, the wet stuff on your forehead and that drips from your armpits, is NOT saline, ie 0,9 % (9 g of salt per litre) like the water in your blood . Perspiration is not nearly that, in fact it may be lower than 0,3%. From here, it does not require a rocket scientist to figure out that if you lose more water than salt, then the remaining salt will concentrate inside the body.
The kidneys are tasked with the function to ensure that the salt concentration in the body remains 0,9%, no matter what. So, you lost a lot of water, you are dehydrating and the salt is concentrating in the blood. The kidneys sense the imbalance and rapidly start to excrete the salt by producing urine.Expensive urine, very expensive.
Yes, the kidneys is now using the water that you don’t have available as a result of perspiration and dehydration to make urine to excrete excess salt that every text book, every medical doctor and everyone else tell you to replenish. So you replenish the salt, and the salt concentration in the blood goes even higher. Putting petrol on a fire!
This myth goes further, ie the salt that you lose is responsible for muscle cramps. So you are advised to replenish the salt to avoid cramps, and then the cramps get worse until you get a heart cramp. But more about cramps and how to avoid them on another occasion. I am off to find myself a glass of water.
A myth may be defined as “a widely held, but false belief or idea”. And that is exactly what this is about, the widely held false belief that you need to replenish salt, as sodium chloride, when you lose water through perspiration.
Usually the nature of a myth is harmless, well at least most of the old wives tales that go around from time to time are harmless. But some myths are dangerous, and this one is no exception. To take in salt when you are dehydrated is inviting serious problems, such as heat stroke, coma and sudden death.
Let us take it from the beginning. When you perspire, like soldiers, athletes and the most of us do, we perspire to cool down the body. In the process, you will lose some water and depending on the conditions, often a lot of water. If you do not drink water during your activity, you are going to dehydrate.
And here is the myth. Last night, reading from Bill Bryson’s ‘”THE BODY, A Guide for Occupants”, the myth resurfaced again. Bill Bryson in his new book explains “…..together with the water, you lose a lot of salt, and you should also replenish that…..”
OK, so do we now return to the 1970’s when we fed soldiers, rugby players and athletes salt tablets? And the late Prof Nic Strydom from the Chamber of Mines almost had a fist fight on national television with the Army Generals who insisted that this myth is true and the late Professor convinced them to stop this dangerous practice that directly caused the death of a number of soldiers in those years? I thought the myth was laid to rest there and then.
The first important fact to remember is that perspiration, the wet stuff on your forehead and that drips from your armpits, is NOT saline, ie 0,9 % (9 g of salt per litre) like the water in your blood . Perspiration is not nearly that, in fact it may be lower than 0,3%. From here, it does not require a rocket scientist to figure out that if you lose more water than salt, then the remaining salt will concentrate inside the body.
The kidneys are tasked with the function to ensure that the salt concentration in the body remains 0,9%, no matter what. So, you lost a lot of water, you are dehydrating and the salt is concentrating in the blood. The kidneys sense the imbalance and rapidly start to excrete the salt by producing urine.Expensive urine, very expensive.
Yes, the kidneys is now using the water that you don’t have available as a result of perspiration and dehydration to make urine to excrete excess salt that every text book, every medical doctor and everyone else tell you to replenish. So you replenish the salt, and the salt concentration in the blood goes even higher. Putting petrol on a fire!
This myth goes further, ie the salt that you lose is responsible for muscle cramps. So you are advised to replenish the salt to avoid cramps, and then the cramps get worse until you get a heart cramp. But more about cramps and how to avoid them on another occasion. I am off to find myself a glass of water.
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