So all you roadies are obsessed with optimizing your Zone 2 rides, but Im still trying to figure out how pre-loading sodium actually works. Ive heard it can help with hydration and endurance, but whats the science behind it? Does it really make a difference in performance, or is it just another gimmick to sell more sports drinks and supplements? And whats the optimal amount of sodium to pre-load - is it a one-size-fits-all deal, or does it depend on individual factors like sweat rate and body weight? And while were at it, whats the best way to pre-load sodium - should I be guzzling sports drinks all day, or is there a more subtle approach? And can someone please explain to me why road cyclists are so obsessed with Zone 2 rides, anyway? Is it really the most effective way to build endurance, or is it just a bunch of masochists who enjoy suffering for hours on end?