Researchers found that getting dehydrated affects our ability to perform tasks that require paying attention, and it can happen faster than you might think. For example, doing vigorous yardwork for a few hours without drinking can lead to acute dehydration, which can make it difficult to focus, drive, and complete tasks that require attention, coordination, or problem-solving. So how much water is enough? There’s no set amount for everyone. It depends on your weight, activity level, and the weather. The best way to gauge your level of hydration is the pee test: If your urine is clear or light yellow, that’s a good sign you’re drinking enough. Bear in mind that alcoholic beverages can dehydrate the body (sorry!). Keep in mind that you need extra liquid in warm weather, and on days spent exercising or being otherwise active, it’s a good idea to “pre-hydrate” with a couple glasses of water an hour or two before the activity. If you’re craving flavor, squeeze some lemon or lime into your glass, or let any combination of fruit, cucumber, and fresh mint leaves steep in a pitcher of water in your fridge.
Source: Dehydration Impairs Cognitive Performance: A Meta-analysis.
“Water is the softest of all things, yet it is the most powerful.” Wayne Dyer