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Can a sodium blast increase the heartrate??(2 posts)

Can a sodium blast increase the heartrate??128
May 2, 2002 6:49 AM
Kind of a weird nutrition question I suppose. But recently, I seem to notice a sort of caffeine effect from a high a sodium, instant lunch product; name of which I'm ashamed to admit(it's like an addiction though..)
I don't care for salt in general. But the last few times I've eaten super salty crap I get a slight but noticable increse in heart rate.
I believe salt has to do with high blood pressure, but that seems more chronic...??
Doc?
It shouldn't -- except...p chop
May 2, 2002 8:13 PM
No Doc here, but as an ICU nurse I can help you with the basic physiology (plus a little something extra):

Normally, eating salt should only make you retain water; retaining water is how salt gives people high blood pressure.

Increased blood pressure doesn't make your heart want to beat faster, rather the opposite, but it can make you more able to feel your heartbeat. (One thing that does make your heart beat faster is dehydration.)

HOWEVER ---

A massive salt ingestion has a (slightly) more immediate effect than water retention: when the salt gets into your body, it "pulls" water out of the cells (osmosis), expanding the volume of fluids, including blood. While an increase in blood pressure doesn't lead to increased heart rate, a sudden increase in blood VOLUME can. This effect has been shown to be more likely in a person with a low resting heart rate.

Now, whether the volume shift from a salt ingestion could produce this effect (called the Bainbridge reflex)
is an interesting question. The experiments that demonstrated it used intravenous fluids to expand the blood volume, not dietary salt. The answer might not be known.

When you say slight but noticable increase in HR, what makes it noticable? Is it the actual number of beats per minute, or do you notice it some other way? What are you doing when you notice it, e.g., do you get up and bike after lunch?

BTW, thinking of the possible objects of your lunchtime fetish, I looked up MSG, but only found links relating it to headaches and allergies. Dang, because I wanted to hate that stuff. No offense if you like it. I still eat stuff with it, too.