Go Hydro tablets are designed to help you stay hydrated when exercising. One drinking tablet consists of main electrolytes such as Sodium, Magnesium and Calcium. You bung a tablet in a bottle of water, wait while it dissolves, then drink it during your ride. Keeping hydrated is one of the biggest concerns for any endurance athlete. Originally designed for the 2008 GB Olympic sailing team, this low-calorie drink tastes great and it is extremely effective for any high-sweat activity.