Drink up, my friends. According to Dr. Kirti Salwe Carter, author of the book The Morning Mind, your brain has a smaller mass in the morning, due to the distribution of fluids around the body and a prolonged period without hydration while you sleep. "Because of this, it is important to drink a glass of water before bed and after waking," they tell Elite Daily over email. "A larger, hydrated brain means increased blood flow, more oxygen, and nutrient availability, allowing for increased levels of concentration, improved mood, and better sleep."