Mind over body
Late summer is the height of the endurance race season. All the ultra 100’s, 24-hour epics, half marathons and extended foot races arrive around August. I guess the organizers know that, except for the few, the proud, the elite athletes who are ready year-round to run 100 miles at a moment’s notice, most people need a spring and summer of pain, sweat peer pressure and pre-registration commitment to get into some semblance of Ultra race survivable shape.
These community endurance events need these common people for the fun they bring, for the registration fees, for their support, for their sponsors to sell stuff too and for the elite racers to whup ass on.
The cliches “mental strength” and “it’s all in your mind” may actually be half true for these events. Sure, you have to be blessed with the mutant genetics, but new theories on fatigue suggest the mind, not your muscles, controls how tired you feel.
Ever thought it strange that, at the end of a long race where you’re just hanging on, you see the end and suddenly find the energy for a sustained burst? That doesn’t fit in with the idea that you get tired because you ran out of energy and your muscles are overwhelmed by lactic acid.
Articles by R. Lovett about the work of exercise physiologists T. Noakes and A. St. Clair Gibson of Cape Town give an idea why. Noakes and St. Clair Gibson think your brain is constantly monitoring physiological processes in your body (levels of glycogen, ATP, lactic acid, oxygen, heat, dehydration etc) and decides when you should feel tired, instigating all those symptoms of exhaustion to slow you down. It does this well before your body is close to its actual physical limits.
Allowing you to run yourself literally into the ground doesn’t make sense from an evolutionary point of view. It’s always nice to have some reserves in case a grizzly bear happened to trundle onto the bike path. Hard to test this by loosing lions on stumbling marathon runners, but it does explain that last lap sprint. Your brain sees the finish is near and it’s OK to let go of a bit extra of this untapped back up.
They’ve measured the percent of muscle fibers contracting as cyclists tire. Typically endurance events use only 30 percent of the muscle fibers in one contraction. The others take a break; it’s like a relay, they run every third lap. As athletes tire, they use less and less fibers even when asked to sprint. Noakes and St. Clair Gibson see this as evidence that the brain is holding rested fibers back. To counter act the claim that these fibers are done in and need the extra rest to recover, they took biopsies of tired muscles and found the still have reserves of ATP, glycogen and fat.
They call this the “governor theory,” where your brain rations what you physically have according to what demands it expects. That last bit – expects – means you can trick and train your brain into performing harder or be tripped up by the unexpected.
A long ride doesn’t feel that tiring at the beginning, often much less so than a shorter ride as your governor rations the fatigue in bigger dollops on the short ride. A surprise hill can throw everything off, creating almost demoralizing fatigue especially towards the end of a race. Suddenly, you have to spread out some limited reserves a lot further. Perhaps that’s why a stiff headwind is so more tiring than climbing a hill. The workload may be the same, but the hill you’d planned for ” even looked forward to ” and the headwind is this unexpected drag.
Stimulants block the signs of fatigue and allow you to push yourself harder, but mental exhaustion is a safety valve; you’ll stop before your body literally collapses and perhaps dies. Once fit interval training produces fast improvements in performance. The muscles may be getting accustomed and better at dealing with lactic acid, but the speed of improvement points to a mental change. Your brain is trained that it’s OK to dig a little deeper into the reserves it’s saving.
Scientists often end up trying to explain the “why” of common knowledge and things athletes have known for years. Everyone pre-rides a course, and hard training always feels like a battle between your body and brain. Perhaps that’s why some athletes come back from life-threatening injuries and illness stronger than before. They’re forced to find reserves they never knew they had. The rugby cliche of “what doesn’t kill you only makes you stronger” lives again.
Alan Braunholtz of Vail writes a weekly column for the Daily. This column, as in the case of all personal columns, does not necessarily reflect the views of the Vail Daily.
Vail Daily, Vail, Colorado
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