Salt guidelines all wrong for hot climates and exercise

The medical establishment has been making the case for some time now that in hot weather / climates you should "stay well hydrated" "by drinking lots of water." They recommend 2 liters per day (8 glasses) or more.

However at the same time the same medical establishment has been saying people get too much salt in their diets and that salt is a killer, and so on and so forth. The problem with this is that increased water intake (and outflow) causes salt to be leached from the body.

In a healthy person if salt levels rise above homeostasis, your kidneys flush it out and your brain sends a thirst signal for you to increase you water intake. However in a healthy person if your salt levels fall BELOW a certain threshold (and this can happen quite suddenly, for example in any environment in which you are sweating heavily and drinking a lot of water) then you can have major damage done to your organs and permanent health repercussions.

Low sodium in the blood is known as hyponatremia and is usually studied in marathon runners. I submit that this is because the medical establishment is centered around cold climates like North America where running a marathon is the only reason you would sweat sufficiently and drink sufficient water to reduce your blood salt levels dangerously.

If you live in a hot climate, like Australia, the heat of summer alone may cause you to sweat and pee out your salt reserves. You need to replenish your sodium levels constantly by adding salt to your food or water. This used to be less of a problem when our food contained ordinary levels of salt, as adapted to our local climate, but now virtually everything you eat has 'reduced sodium' (a direct consequence of medical guidelines.) This can be a death sentence in the heat. You may not know what's wrong with you and you can die in the heat for lack of salt.

You should be consuming approximately 1.5 teaspoons of salt a day (including that which you eat in food) to maintain healthy sodium levels. If you do sustained physical activity in the heat ( temperatures above about 24 C ) you should take salt with you as well as plenty of water. If you feel ill and especially if you stop sweating while still feeling hot and still being well hydrated you should consume some salt and rest in the shade.

http://cjasn.asnjournals.org/content/2/1/151.long
http://www.rice.edu/~jenky/sports/salt.html
https://www.beverageinstitute.org/expert/understanding-exercise-associated-hyponatremia/

 

I think this is a myth. Even processed foods are now increasingly low sodium as everyone scrambles to comply with establishment practices.

For example: http://www.mcdonalds.co.uk/ukhome/w...hat-is-the-salt-content-of-your-products.html

I take McDonalds to be the poster child of god-awful fast food. According to their online calculator here http://www.mcdonalds.co.uk/ukhome/meal_builder.html a big mac and medium fries has 2.92 grams of salt in it. If your other major meal of the day had no salt then you would be less than 3.5 grams recommended intake.

However that 3.5 grams is historically very low. Before refrigeration salting meat was one of the few ways to preserve it and the average intake of salt (in addition to preservative salt) was several times what it is today (3 teaspoons or 15 grams was recorded on ration cards from the second world war for example.) Meats which are still salted today like ham and bacon are actually salted with sodium nitrate -- which is not the same as sodium chloride as far as your body is concerned.

http://www.saltinstitute.org/news-articles/history-of-salt-consumption/

When the body lacks sufficient (according to it, not the WHO) the body goes into sodium conservation mode. This is where it releases renin and aldosterone. Aldosterone in particular is known to physically damage heart tissue.

http://ajh.oxfordjournals.org/content/25/1/1.short
http://www.clinsci.org/content/114/3/221.abstract

Consider that if you go to the hospital for any sort of major trauma you are given an IV containing saline solution. Your cardiovascular system *is* a saline system. They certainly don't give you pure water because pure water would probably kill you. Consider also that all of the Cl in H-Cl that your body makes for your digestion acid has to come from somewhere -- and that is typically salt.

The idea that you should drink only pure water while you output salt constantly, and that salt is bad for you in all but trace quantities seems extremely dubious in light of historical and current evidence and the basic mechanisms at work. But that said, I'm not a doctor. I am going to keep researching it in the interests of my own health.

 

It's mostly sodium chloride and you're well hydrated precisely because you're drinking salt water in the morning (as I now do).