I used to drink water only when thirst climbs up my throat; over the course of last year or two, I gradually increased the frequency and amount of water intake, to about 2.5 liters per day. Not an extraordinary amount, but quite effectively, it has alleviated my chronic stuffy nose.<p>Slowing down aging, improvements of digestive system, etc. I can't really feel. But the freedom to breath through my nose, which used to occur only after a hot shower, to be liberated from having to gape my mouth like a dazed cat all the time, is a huge reward in itself.<p>Anecdotal, of course. But I've rule out tons of other variables already (location, allergen, air humidity, temperature, diet, etc.) for this chronic---and inherited---condition, and I'm reasonably confident in my uneducated guess that hydration has something to do with it.