I think all medical studies should be taken with a grain of salt, and maybe with lime and tequila as well. There's one thing a medical study has in common with a Hollywood starlet's Reality Show: it's complicated.
The conventional wisdom has always been thusly:
1. High salt intake = high blood pressure
2. High blood pressure = higher likelihood of strokes and heart attacks
3 Strokes and heart attacks = very bad, to be avoided
I'm fine with points 2 and 3. Point 1 is the questionable part.
This advice is good if you're a couch potato.
It's not so good if you work out a lot . Then the process runs (or walks, or bicycles) more like this:
4. Exercising a lot = sweating a lot
5. Sweating = loss of salt
6. Loss of salt = high blood pressure (refer to points 2 and 3 above)
To quote my hero Dr. Mirkin, from whom this information was blatantly
If you exercise heavily and restrict salt, you will not replace the salt you lose through sweating, which can cause high blood pressure as well as fatigue, cramps and muscle pain. When the body is low in salt, the adrenal glands produce large amounts of aldosterone and the kidneys produce renin, which constricts arteries and can raise blood pressure.
Researchers at Albert Einstein College of Medicine showed that people on low-salt diets are actually more likely to suffer heart attacks than those on high salt diets (Journal of General Internal Medicine, June 2008). They analyzed data from the Third National Health and Nutrition Examination Survey (NHANES III) of American adults. Dr. Hillel W. Cohen, lead author of the study, stated, "Our findings suggest that for the general adult population, higher sodium is very unlikely to be independently associated with higher risk of death from heart attacks."
Every time I come across a study that seems to contradict everything I'd heard before on the subject, my first instinct is to go back to bed and pull the covers over my head. Trying to juggle several different theories at one time causes the brain to overload, and I want to press my hands against my ears and sing la la la until all the theories go away.I Just Don't Want to Know.
But sometimes what looks like a 180 degree contradiction isn't. This study refines the previous theory rather than opposing it. You can steer a middle course between no-salt and becoming a salt vampire, like that woman on the original Star Trek. (Am I the only person who remembers the original Start Trek?)
Life is not One Size Fits All, so why should health advice apply equally to all the people all the time? Pass me the tequila and lime. Don't forget the salt.