Yes,
@Burnham, I'm a big believer that people commonly go around dehydrated
Dehydration - Symptoms and causes - https://www.mayoclinic.org/diseases-conditions/dehydration/symptoms-causes/syc-20354086 without realizing it.
There is a good range of hydration without constant intake.
Somewhere I have heard that thirst in the first indicator of needing to replenish water, as a result of being depleted. It's like hunger, as in if your noticeably hungry, you're late in eating. It's like being at the bottom of the oil dipstick, rather than being in the 1-quart variable operating range.
I've been jokingly known as Clear and Copious Kroll, as it came from our daily Safety Meetings in my previous work place in Nevada (proper hydration and good diet...watch for the Umbles...mumbles, grumbles, fumbles, stumbles...aim for clear and copious urination).
Once, while working on the Eureka Sand Dunes in Death Valley NP on a restoration project, where there wasn't really a place to walk to pee in private, my crew tried to secretly out-pee me. They told me about it after the day was done. hahaha.
Hyponatremia seems to be a rare situation, and avoided with normal food intake. When I took a Wilderness First Responder class in college, the instructors told of Grand Canyon Hikers being examples of sufferers of hyponatremia
Hyponatremia - Symptoms and causes - https://www.mayoclinic.org/diseases-conditions/hyponatremia/symptoms-causes/syc-20373711, as it was hot, people had water accessible, and sometimes didn't eat enough in the heat, and were sweating a ton.
I've never run across hyponatremia, but have run across dehydration so many times I've lost count.
Once, in Lake Tahoe, one of our international volunteers started acting loopy. He was dehydrated. When asked about his urine output, we got a new catch phrase...Brown and stinky, take a drinky.
WFR trainers said, "Don't be a DIChead"...Disoriented, Irritable, Combative--symptoms of dehydration.
If you want to get an irritable, combative response from someone who is mentally unfocused from dehydration, tell them they are dehydrated.
I've observed this in myself, when I've tried to tell myself that I am getting dehydrated.