Urine Trouble if it's Dark

I don't know who first told me this or where I read it, but after the surgery I was firmly afraid that I was not getting enough water.

There were warnings about drinking throughout the day, keeping hydrated, and generally making sure I was drinking water; not juices, not carbonated drinks, but water.

It was worse now that I wasn't eating as much as I used to. You have no idea how much of your water actually comes from the foods you eat, and when you overeat you get even more fluids indirectly from your diet.

The fear was in the darkness of urine. If the urine was a dark yellow, the story went, it meant I was dehydrated.

There were times it was dark. I'd drink until it was running nearly clear. There were times when I was drinking and I wasn't even thirsty, just to make sure I was keeping hydrated.

I just finished reading Don't Swallow Your Gum! by Dr. Aaron E. Carroll and Dr. Rachel C. Vreeman, and it dispells a lot of myths and lies about health and how the body works. Among them: how much water your body needs.

It's "common knowledge" that you should drink eight glasses of water a day. The problem is that is wrong. Back in 1945 the Food and Nutrition Board of National Research Council said that adults should get 2.5 liters (which translates into roughly 8 glasses of water) a day and that most of it comes from prepared foods.

That in itself would be fine except that people like things in trite, easy to remember tidbits. That advice somehow had the "food" part chopped out: thus the "8 glasses of water" myth.

The body apparently works to regulate fluids on its own quite well. Ever heard that when you're thirsty, you're dehydrated already? Well, the book addressed that too. Apparently your body, when it senses that it needs to retain water, releases a hormone called vasopressin, signaling the kidneys to retain water. This regulates automatically how often you feel the urge to go number one. So feeling thirsty doesn't mean that you're dehydrated.

But the most important...or at least, relevant...question addressed was on page 24. "Your Urine Should Be Almost Clear."

The book states this is a half-truth. To quote:
The color of the urine depends on its osmolality, which is the technical term for how much stuff is dissolved in the liquid. When there is more stuff dissolved in a given volume of urine, the urine is more concentrated, and therefore it looks darker. However, the osmolality of normal urine can be very different from person to person. One specialist in fluid regulation tested teh urine of sixty-nine healthy young adults and measured the average volume and concentrations of their urine. For this group, all of whom were considered well hydrated and healthy, the average volume of urine was 1.5 liters per day and the average concentration was 600 mosmol/kg H2O. At this average concentration, urine is moderately yellow in color, which could be interpreted as "dark" compared to the recommended "clear" or "pale yellow" you may think of as your goal. This concentration is, in fact, well within the normal range. Most of the time, normal urine from a healthy, well-hydrated person may be very yellow.

So urine color being yellow or "darker" doesn't mean you're dehydrated. I was worrying over nothing! Live and learn...