Depending upon you sweat rate and the weather, you lose anywhere from 1 to 2 quarts of perspiration an hour.
On rides, you must replace this fluid loss with more than just water because you're not only losing H2O, but also vital nutrients. Energy drinks are best because they contain the electrolytes and nutrients lost through sweating.
Energy drinks also provide carbohydrates to fuel the muscles. But it's got to be an energy drink you enjoy because if it tastes good, you'll drink more. And, if it tastes bad, you won't drink enough, if at all.
When you're carrying energy drink in both bottles, lower the concentration in your second bottle
because as you fatigue and heat up, you'll likely prefer less flavor and sweetness. If you're riding hard, it's also important that your energy drink isn't too concentrated. Too rich a mixture can upset your stomach and even slow down or prevent water absorption.
Preparing for a cycling event or race? Be sure to experiment while training to find the drink that's most compatible with your system. That way, you'll be drinking something that works and you won't experience stomach aches or cramping during the important ride. Also, train with bottles and hydration packs to determine which works best. The latter are great for long rides because of their large capacity. Plus, the hose makes it much easier to drink enough. So on bumpy terrain such as in an off-road race/ride they can offer an advantage.
To make sure you're properly hydrated before an event, check your urine. It should be pale yellow or clear. Dark yellow and strong-smelling urine is a reminder to drink a few more glasses of water, although vitamin pills can have a coloring effect as well. Another key sign of proper hydration is having to get up during the night before the event to urinate.
When the temperatures start soaring, insulated bottles and hydration systems can keep your water cooler, which will help keep your body temperature lower. You can also freeze water in your bottles the night before. But, fill only half way so you can top it off with drink before the ride. The ice in the bottom will chill the liquid for a while. Ice in a hydration pack can also help cool your torso.