You should check your sweat rate - simply take your weight before the ride - ride for an hour and weigh yourself again - add any fluids you took in to keep it honest. there is a performance loss from as little as 3% loss of fluids....you should use a bit more comprehensive hydration drink like accelerade, cytomax, or revenge, rather than gatorade - much better suited to what you are doing....those salt lines indicate performance decriment and should be avoided as much as possible