Racing Through the Brain’s “Eyes”

Poets have often written about how the eyes are the windows to the soul. For endurance athletes, the eyes are also a portal to the brain’s inner workings. Using the example of a ten-mile road running race, let’s take a journey through the eyes of a competitor’s brain. The challenge for our fictional runner is to finish the race in just under eighty minutes, a decision based on his MAF Test results (data), course terrain (data), past race experience (memory), and overall general feelings (emotional).

Throughout the race, the brain will monitor the body’s activity through messages sent by nerves informing the brain about muscle balance (physical capability), terrain (up and down hills), fat and sugar burning (energy availability), body temperature (a reflection of metabolism), foot stress (influence of shoes and road conditions), pain (emotion), and many other factors such as heart and breathing rate. These factors provide the brain with sufficient information to create a highly effective race strategy.

广告：个人专属 VPN，独立 IP，无限流量，多机房切换，还可以屏蔽广告和恶意软件，每月最低仅 5 美元

Even before the gun sounds, our runner’s body and brain are continuously sending messages back and forth in preparation for the event. If he goes out too fast, his brain will make the appropriate changes to slow down, both consciously, when he hears the first mile split, and subconsciously (by reducing muscle power to slow him down).

After the second mile, the brain slows the pace because it has determined that the current speed is too difficult to maintain. As the gravitational stresses fluctuate with the uphills and downhills, continuous adjustments are made with pace, muscle function, and energy needs. Perhaps he is checking splits with a watch, consciously and subconsciously estimating a finishing time.

By mile five, the halfway mark, the brain assesses where he is in relation to the finish line and what it will take to maintain current pace. This includes reserving the energy and physical capability. But subtle muscle imbalance that previously existed is now worsening with the physical and metabolic stresses of the first five miles. The brain has been noticing these changes, and now knows it must make take action. It sends messages from the motor cortex down through the spinal cord to create the most effective compensation for the reduced power output of certain muscles by providing more contraction to other muscle fibers. This is accompanied by adjustments in fuel use, attempting more fat burning to conserve sugar. The result of these neurological adjustments is that the pace is slightly reduced.

By mile seven, the body’s fuel gauges indicate a problem—there is still too little energy coming from fat and too much from sugar. This imbalance has caused a slight reduction in blood sugar with too much glycogen use. This complication resulted from trying to keep pace with nearby runners up a hill in mile six—an emotional situation the brain must now adapt to. Because of these metabolic changes, the mile seven pace must be adjusted downward. Also, dehydration has caused too much of an increase in body temperature and water must be consumed; our runner also pours water on his head for added cooling. As a result of these effective adjustments, he recovers and runs mile eight at a slightly quicker pace.

Now that the finish line is mentally within his reach, adjustments are made near mile nine. These include making conscious decisions to continue quenching thirst (which prevents too much dehydration and controls rising temperatures), factoring in pain tolerance (accepting the discomfort knowing the race will soon end), adjustment of breathing (a bit deeper), and slightly shortening stride length to cut down on physical stress. All this takes place while the brain continues adapting from moment to moment to all the other physical, chemical, and mental requirements, including muscle balance, energy production, and stress control.

During the last mile, if his brain and body coordination was successful throughout the race, he has an increased pace and finds himself crossing the finish in reasonably good shape, perhaps with a stronger kick at the end. If not, he becomes a wounded warrior, limping erratically through the final painful mile. Or worse, he collapses before the finish line because his brain has shut down the body to prevent serious damage. Consider Julie Moss in the February 1982 Ironman Hawaii race—she was forced to crawl those last few feet.

This continuous back-and-forth communication between the brain and body during the race comes with another interesting feature: trial and error. This is due to the brain’s periods of “uncertainty” where it must make a particular physiological adjustment during a race, then wait to gauge the result. For instance, if, during mile seven the brain determines that the blood sugar levels are dropping too low, some physical adjustments are made—perhaps reducing muscle contraction to conserve sugar, which slows the pace, or converting more glycogen to glucose. Then the brain may have to wait again to see if these changes improved blood sugar; if not, it considers what other changes may be necessary, such as further slowing or even stopping at the water station. But while the brain is preoccupied with such activities, all this compensation can take away from better performance by using up more energy, ultimately slowing one’s finishing time. Over the years, I have noticed that experienced athletes who are healthier physically, chemically, and mentally can maintain better pacing through a long event with less of the brain’s trial and error periods, which can also increase wear and tear, contribute to injury, and slow recovery.