Chess is a competitive sport in the classical meaning of the word. the accumulated time of training is one of the most important factors for chess and sport competence. To obtain a high level of competence, chess players and athletes alike must spend up 10 years of specific training. In chess and classical sport energy needed for brain activity is first derived from glycogen stores in brain, muscles and liver and later from adipose tissue. Both, chess and classical sport rely on shared energy from glycogen and fat. When the brain needs additional energy, muscles and liver share energy with the brain. When muscles need additional energy, brain complies with the request of muscles. Energy expenditure, O2 uptake and CO2 production during chess games are similar to those obtained during a marathon. Mental and physical fatigue begins with similar metabolic states: deprivation of glycogen. For competitive chess, athletes should be in good physical condition. Mental profiles of chess players and other athletes correlate with processes such as attention, conflict control, memory, motivation and recognition. In chess there exists no gender-specific excellence; glycogen availability, however, is less developed in female chess players. In chess and in classical sports, the brain, spinal cord, nerves and muscles cooperate in complete harmony. The brain commands everything: in chess the figures, in sport the cellular receptors (baro-, lactate-, gluco-, metabo-, chemo-, thermo-, respiratory-) “send” signals via eyes or metabolic changes to the brain. The brain then decides, what to do: in chess, the player moves a figure; in sports, muscles react according to demand.