Thirst adversely affects your mental fitness and mood

In summary: To achieve your maximum mental performance, it is extremely important to drink something before you get thirsty. You should distribute your intake of liquid appropriately throughout the entire day. Drinking the necessary quantity of liquid only in the evening is not enough to maintain a high level of mental fitness.

Zeitschrift der Gesellschaft für Gehirntraining e.V., Heft 2.2001. Dr. med. Graessel, Clinic for Psychiatry and Psychotherapy of the University of Erlangen