Whats the actual science behind the claim that sports drinks are necessary for rides over 2 hours, and at what point does the added sugar and calories in sports drinks become counterproductive to performance? Is it purely based on the rate of sweat loss, or are there other factors at play that make water insufficient for replenishing lost electrolytes? And what about the varying levels of electrolytes in different sports drinks - is there any real-world evidence to support the idea that these differences make a tangible impact on performance, or is it just marketing hype? It seems like every sports drink manufacturer claims their product is the best, but what does the actual data say?