Noakes, with several colleagues, began to review evidence of what happens to endurance athletes under extreme conditions. They found no evidence for physiological failure happening within the muscles; instead, it appeared that the brain was telling the muscles to stop. The brain, sensing an increased heart rate and rapidly depleting energy supply, literally puts the brakes on the body. At the same time, the brain creates an overwhelming feeling of fatigue that has little to do with the muscles’ capacity to keep working. As Noakes puts it, “Fatigue should no longer be considered a physical
...more
