Brain
At rest, the human brain receives 15% of total cardiac output, and uses 20% of the body's energy consumption. The brain is normally dependent for its high energy expenditure upon aerobic metabolism. The brain as a result is highly sensitive to failure of its oxygen supply with loss of consciousness occurring within six to seven seconds, with its EEG going flat in 23 seconds. If it affected the oxygen and glucose supply to the brain, the metabolic demands of exercise could therefore quickly disrupt its functioning.
Protecting the brain from even minor disruption is important since exercise depends upon motor control, and particularly, because humans are bipeds, the motor control needed for keeping balance. Indeed, for this reason, brain energy consumption is increased during intense physical exercise due to the demands in the motor cognition needed to control the body.
Read more about this topic: Exercise Physiology
Famous quotes containing the word brain:
“Bear with my weakness. My old brain is troubled.
Be not disturbed with my infirmity.”
—William Shakespeare (1564–1616)
“It is more than likely that the brain itself is, in origin and development, only a sort of great clot of genital fluid held in suspense or reserved.... This hypothesis ... would explain the enormous content of the brain as a maker or presenter of images.”
—Ezra Pound (1885–1972)
“Progress celebrates Pyrrhic victories over nature. Progress makes purses out of human skin. When people were traveling in mail coaches, the world got ahead better than it does now that salesmen fly through the air. What good is speed if the brain has oozed out on the way? How will the heirs of this age be taught the most basic motions that are necessary to activate the most complicated machines? Nature can rely on progress; it will avenge it for the outrage it has perpetrated on it.”
—Karl Kraus (1874–1936)