"Drink more water!" It's the easiest health advice around. Tired? Headache? Trying to be like Tom Brady? Just drink more water. But as a nephrologist, I get asked all the time: How much is the right amount? And the truth is... we don't really know. 🧵 - ThreadSky

fperrywilson.bsky.social • 95 days ago

"Drink more water!" It's the easiest health advice around. Tired? Headache? Trying to be like Tom Brady? Just drink more water. But as a nephrologist, I get asked all the time: How much is the right amount? And the truth is... we don't really know. 🧵

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fperrywilson.bsky.social•95 days ago

(If you'd like the article version of this tweet thread, you can find it @medscape here):
https://buff.ly/4fJmAHN

fperrywilson.bsky.social•95 days ago

I can tell you how your brain and kidneys work together to manage water balance, adjusting your urine from 50 mosm/L to 1200 mosm/L as needed. But I can't tell you how much water YOU should drink. Not for lack of trying to figure it out.

fperrywilson.bsky.social•95 days ago

A few certainties:

Without water, you die. Kangaroo rats can survive on food alone. Humans? Not so much.

You can also die from drinking too MUCH water. Excess water dilutes your blood sodium, potentially causing seizures or worse.

fperrywilson.bsky.social•95 days ago

So, somewhere between zero and 20 liters/day is safe. Great. Super helpful, right? What about the sweet spot? The recommendations (e.g., 8 cups/day or 3 liters for men, 2+ liters for women) sound precise, but they’re… mostly made up.

fperrywilson.bsky.social•95 days ago

Enter: A study from UCSF, published in @JAMANetworkOpen, which finally dug into the data on how much water we should drink. They focused on the gold standard: randomized controlled trials (RCTs). Spoiler: The evidence is… underwhelming.
https://buff.ly/3AQs18S

fperrywilson.bsky.social•95 days ago

After reviewing nearly 1,500 papers, they found just 18 RCTs of water intake changes. Eighteen! These studies looked at water's effect on:

Weight loss
Fasting blood glucose
Headaches
UTIs
Kidney stones
Quality of life

(Note the lack of "skin tone" or "detoxifying" effects)

calicoday.bsky.social•93 days ago

📌

kentkidneydoc.bsky.social•94 days ago

Great thread this 👍🏻

criticallyspeaking.bsky.social•94 days ago

I’d seen your nice piece in Medium. People are definitely confused about this. Thx

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