Wednesday, November 17, 2004

On Colds and Fluids

The baby has been sick this week with a nasty cold. After a few days, I started coming down with symptoms myself. Determined to do what I could to get over it, I decided to make sure I took my daily multivitamin and drank plenty of fluids. But wait, I thought, ‘drink plenty of fluids’ sounds like it might be one of those tenets of medicine that’s just been passed down through the years without any scientific basis. It’s obvious that drinking is very important if you have, say, repeated episodes of diarrhea that make you a dehydration risk. But on the other, people with run-of-the-mill colds don’t usually have diarrhea, and often have the opposite problem. Is there any scientific justification for not following your body’s internal cues of thirst in this matter?

I asked Google for wisdom.

The only thing I could really find was a commonly cited study early this year (as in this article) offering some evidence that drinking extra fluids may actually do more harm than good, because respiratory illnesses tend to trigger a water-retaining reflex; increasing consumption on top of this may upset the body’s salt balance. The study was very far from conclusive. Doctors generally say they dispense this advice in the belief that it reduces congestion by thinning mucus secretions. This would make the patient more comfortable, and also reduce the chance of a secondary sinus infection. Coming from a family where secondary sinus infections are the norm, I decided, on this occasion, to go with the fluids. I didn’t drink like a fish, but I made a conscious drinking effort that definitely upped my hydration level, taking care to not drink too much in any given sitting, and to eat small snacks to keep from excessively diluting my salts. I don’t think I’ve made this kind of effort on any previous cold.

I’m not really surprised that this common wisdom has never been carefully studied. There’s no direct commercial interest in doing so. But one would think this would be the kind of study a government agency or non-profit could commission. After all, the common cold supposedly costs the U.S. economy $40 billion annually. Anything to reduce the number of sick days, doctor visits and ineffectual antibiotic prescriptions would seem like a good idea.

And I’m curious as to how or why the water-retention response to respiratory sickness might have evolved, but this not a question I expect can be easily answered. There was probably nothing ‘common’ about colds prior to the development of agriculture, and I don’t know enough to say whether the water-retention reflex is triggered directly by the ailment or by an evolutionarily advantageous immune response. If it was an evolved response, what was the advantage?

Oh, the result of my ‘experiment’? Inconclusive. I’m just one person, after all, and who’s to say whether I had an actual cold robust enough to cause the usual grief?. But I seem to have gotten over this cold with ease, breathing easily during most hours of the day and skipping the gummy green horror of a sinus infection.

Now you know. I’m truly a blogger now.


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