Most CrossFitters fall short on optimal performance in terms of hydration. That can lead to decreased performance and early fatigue. There is a lot that can work against being optimally hydrated. Too much coffee, too much alcohol and too little water are the obvious ones.
However, a big part of the problem is timing of hydration. Too many athletes try to chug water before a workout or drink during a workout thinking they are getting properly hydrated.
If you are sipping a water bottle right before or during a workout, it is too little, too late. That bottle during your 20 minute AMRAP isn’t going to have as much of an impact as your hydration habits in the other 23 hours a day. When you head to the Box, the hydration you start with is the hydration you are stuck with.
For optimal hydration, I recommend athletes re-hydrate starting right after their workout. Hydrating properly is essential to recovering for the next day’s performance.