Hydration status significantly affects cognitive performance, as even mild dehydration can impair concentration, alertness, and short-term memory. The brain relies on water for optimal function, and inadequate hydration can lead to fatigue and difficulty focusing. Studies indicate that staying well-hydrated supports better mental clarity and decision-making abilities. For optimal cognitive performance, individuals should aim to drink sufficient fluids throughout the day, especially during physical activity or hot weather when dehydration risk is higher.