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:
“My brain is dull, my sight is foul,
I cannot write a verse, or read—
Then, Pallas, take away thine Owl,
And let us have a lark instead.”
—Thomas Hood (1799–1845)
“When our brain feels too weak to deal with our opponent’s objections, our heart answers by casting suspicion on their underlying motives.”
—Friedrich Nietzsche (1844–1900)
“Men should not labor foolishly like brutes, but the brain and the body should always, or as much as possible, work and rest together, and then the work will be of such a kind that when the body is hungry the brain will be hungry also, and the same food will suffice for both; otherwise the food which repairs the waste energy of the overwrought body will oppress the sedentary brain, and the degenerate scholar will come to esteem all food vulgar, and all getting a living drudgery.”
—Henry David Thoreau (1817–1862)