Pedialyte has its fans among adults. Managers and clerks at a couple of nearby shops say in summertime they have to stock up on extra generic pedialyte for the construction and road crew laborers.
That surprised me because I would have assumed the higher concentration of sodium and potassium might cause indigestion and diarrhea. If you've worked construction or pretty much any heavy labor industrial job, you know you don't get much time for potty breaks, and some union job breaks are heavily regulated. When I moved freight on a union loading dock we got two 15 minute rest/bathroom breaks and one 30 minute meal break per shift. No variations in time. If you needed a bathroom break off that schedule you'd better be damned quick and well ahead of schedule on your loading/unloading. No extra drink breaks either, and they frowned on carrying your own water on the dock although some guys wore belt canteens.
So either the higher concentration of electrolytes in pedialyte isn't too bad, or you get used to it. Maybe the guys who bought it diluted it with water, I dunno.
Some folks might be able to get by on plain water and a good diet, but I can't. Oddly, my bouts with stomach cramps, muscle cramps and other dehydration symptoms have never occurred during the hottest weather, even though I've bicycled up to 65 miles in Texas summer (and a local cycling friend rides full centuries once or twice a week year 'round, regardless of heat). My bouts with cramps have occurred on relatively cool overcast days. My best guess is I'm more cautious in summer but let my guard down on days in the 60s-70s and forget to drink enough.
Last bout with stomach cramps so severe I couldn't keep riding was last June on an overcast, cool morning after pushing pretty hard for an hour with hill climbing repeats. I carried some NUUN tablets but didn't premix them in my water bottles. I rested under a bridge, drank a bottle with the NUUN added, popped a glucose tablet and was fine within 30 minutes and finished another 20-30 miles on flatter, easier terrain.
But I envy folks who don't need this stuff and can still churn through exercise or work on hot days with plain water.
I've tried all the popular sports stuff, including NUUN tablets. The only problem I had with NUUN and other tablets was summer humidity and my own sweat thwarting even sealed ziplock baggies, making a sticky mess inside the baggies. Unfortunately the tablets were slightly larger in diameter than the glucose tablets I also carry for emergencies (I've been prone to hypoglycemia bonks since childhood), so the NUUN tabs wouldn't fit in the same sealed plastic tube with the glucose tabs.
I settled on DripDrop when I can find it (it's pricey and relatively scarce outside of pharmacies), or the much cheaper Propel. Both come in single serving Mylar packets tiny enough to fit even the most minimal saddle bag. And it can safely be tucked into a sock without sweat penetrating the Mylar packet. The DripDrop tastes good, slightly tangy. The Propel has that nasty bitter artificial sweetener flavor, but it works and it's cheap.
Another good 'un in sealed single serving Mylar packets is Emergen-C, which contains more vitamins B and C, zinc, etc. The packets are larger than the DripDrop and Propel but still small enough to tuck into a minimalist saddle bag, jersey pocket or sock and stay dry no matter how sweaty I get. Tastes okay, a bit like orange-vanilla creme sorbet, no nasty bitterness. Walgreen's was blowing out their stock of short dated Emergen-C a couple of months ago and I bought dozens of packets for a nickel apiece.
Anyway, the NUUN and other tablets worked great, but the DripDrop, Propel and Emergen-C in single serving Mylar packets keep better for me in high humidity, or tucked into my sweaty jersey or sock. And my Serfas Speed Bag has little slip pockets just large enough for these electrolyte packets.