[electromagnetic]

Dark urine is a sign of a lot of things, but also dehydration.

Frequent urination is a sign of a lot of things, and also over-hydration.

However, assuming either are related to your present hydration is dumb.

If you're regularly saying "my urine's dark, I must be dehydrated" you should probably be visiting a doctor.

[niels_olson]

> If you're regularly saying "my urine's dark, I must be dehydrated" you should probably be visiting a doctor.

um, well, maybe, but it is accurate (and interestingly, a bit more Bayesian) to say "Hmmm... my urine appears to be darker than it was previously. Without evidence supporting a competing hypothesis, this is most likely because I'm relatively closer to the lower end of normal total body volume". Competing hypotheses include rhabdomyolysis, acute renal injury, chronic renal injury, and all the many things that cause those sorts of end organ damage.

I know HN has at least on board-certified nephrologist lurking around. perhaps he'll chime in.

source: I'm a physician.

Also, I think Noekes raises some very interesting points. I'm a little concerned by the tone of this article, though overall I'm glad the author made the effort to write it. Things like saying Noekes only found 6 instances of heat exhaustion found in the setting of long-distance running are suspect. Doing a lit review is suspect, and in a case like heat exhaustion, it's very tricky to demonstrate the literature reflects the population. Do you really think every patient with heat exhaustion after a marathon got a case report written up? I don't.

[AndrewOMartin]

The fact that there will be a potentially huge percentage of heatstroke cases going unreported doesn't destroy the claim that a body temperature of over 45 degrees is rare, though it may weaken it.

I don't really think every patient with heat exhaustion after a marathon got a case report written up, but I don't care.

[underdown]

As a cyclist from Arizona I stopped reading after seeing that. Complete BS. Lying via omission to support your claim is not a great way to inspire trust.

[dbbolton]

I can't tell if you are agreeing with me or arguing against me because you didn't get the point of/read all of my comment. In case it's the latter:

>However, assuming either are related to your present hydration is dumb.

That's exactly why I said "a symptom alone never makes a diagnosis" and "you can't assume you are dehydrated/your kidneys aren't working right based on those signs by themselves".