@Kevin - physicians are quite expert at fluid management. All of them, but especially any in family practice, internal medicine or its subspecialties, anesthesiology, emergency medicine, or any surgical specialty. Those physicians manage intravenous hydration all day, every day, your suggestion that they don't understand what they are doing is laughable. As is your suggestion that one cannot induce hyponatremia by excessive water consumption. Please google "non-psychogenic polydipsia with hyponatremia"
Products designed for running a distance race do not translate especially well for hiking. I use endurolytes tablets when running for electrolyte replacement, along with plain (free) water for hydration, and mango baby food squeeze packets for calories / nutrition. This combination is great because they are the most healthful options I can use without breaking stride.
I don't use any of these when I'm hiking (except plain water). These products are great because they can be consumed on the run. I run endurance events at seven to eight miles per hour. Even my fastest hiking its half that pace.
At three to four miles per hour, one can consume real food that he likes. My favorites for the trail are salty / sweet Sahale snacks nuts, organic beef jerky, and homade empanades. Plus plain water. I also bring some fresh colourful fruit like blueberries or fresh mango. This provides electrolytes, anti-oxidants, micronutrients, calories, and hydration.
One should consume enough plain (free) water with this food while hiking that he is making clear urine every one to one and a half hours. Needing to urinate more frequently than this indicates excessive water comsumption. One should also make clear urine in everyday life, else he is putting undo strain on his kidneys and setting himself up for kidney stones.