Anyone who has participated in an athletic event who was trying to seriously beat the other contestants knows of exercise fatigue, a.k.a. “hitting the wall” or “bonking”. Your legs feel like lead, you can’t breathe fast enough for your oxygen starved body and your heart feels like it’s going to explode. Is it the same situation that a car is in when it runs out of gas? The pedal is down to the floor but no life from the engine. There is some fascinating research on this topic that goes beyond the old “is it mental or is it physical” question.
Several things happen when one hits “the wall”. Lactic acid builds up (it’s really lactate and not lactic acid. It become lactic acid when lactate is exposed to air). The heart reaches the limit of blood flow. The exercise to air ratio moves into such a deficit that further exercise come to a halt. Here is what happens: At low running speeds, your effort is primarily aerobic (with oxygen). At higher speeds, your legs demand energy at a rate that cannot be met so you have to use fast-burning an-aerobic (without oxygen) energy sources. The problem is that muscles contracting without oxygen produce lactic acid. However, we are not cars that have run out of gas. We have this thing called a brain that complicates things more than we realized. It doesn’t matter if it’s the heat, or cold, or screaming muscles, or lactic acid, it’s how the brain interprets the signals that counts. But there’s a bigger problem. You can hit the wall with a heart rate well below max, modest lactate levels and muscles that still twitch on demand. The physiological indicators do not match the perceived effort.
Consider this Yale University study. A group of volunteers were given an “indulgent” high calorie milk shake or a “sensible” low calorie shake. The appetite hormones of the group given the high calorie shake plunged after drinking it, but did not change when they drank the “sensible” shake. Problem was, the milk shakes were identical! In another study 35 volunteers trained three times a week for an hour at a time on stationary bikes. Half the volunteers did “brain training”, cognitive tasks like selecting the target figure out of a variety of shapes, to produce mental fatigue; the other half just rode the bike. After twelve weeks the physical only training improved their time to exhaustion by 42%. The brain trained group improved by 126%! Their advice…if you are training for a race train when you are mentally fatigued…like after work. Then there is this thing called VO2 max, the ability of the muscles to utilize oxygen. The higher the VO2 max the fitter the athlete…or maybe not. Endurance athletes have hearts that pump so powerfully that the blood does not have time to load up with oxygen as it passes the lungs. In all out exercise, we see measurable drops in available oxygen levels. There’s actually a name for it…exercise induced arterial hypoxemia. So, you have extremely fit people that when looking only at their blood gas levels appear to be couch potatoes. A person under hypnosis touched by what he/she thinks is a red-hot poker (actually the tip of a pen) produces a blister. In another study 30 elite swimmers were put through a series of pain tests by cutting off circulation to the arm with a blood pressure cuff and having them clench/unclench their fist. These swimmers were compared to club-level swimmers and non-athletes. The pain threshold was the same for all three groups. The pain tolerance was 132 contractions for the elite group, 89 for the club and 50 for the non-athletes. Their conclusion…train to pain. Pain tolerance is linked to the type of training done. Athletes that train using medium intensity workouts do not increase their pain tolerance; high intensity workouts increase pain tolerance, by as much as 41% in some studies. No pain no gain appears to be true. The last study is particularly mind-blowing. There is an instant performance boost when you ingest a carbohydrate drink. There is also a performance boost when you take it in and immediately spit it out; it never enters the bloodstream. Further research found the mouth has sensors that relay the mere presence of carbohydrates to the brain.
My training is atypical. I’m a tower runner. Tower runners run up flights of stairs as fast as possible to benefit some cause like disabled veteran and first responders or those with respiratory diseases (Fight for Air Climbs). The buildings are big, as many as 108 floors. Try it sometime. Next time you are in a building use the stairs, go to the top, take the elevator down and repeat 10 times. Don’t do it if you need to remain socially acceptable. You will sweat profusely. Your legs turn to lead, your heart feels like it will explode and you can’t no matter how hard you try breath fast and deep enough. My training is atypical because I set the workout to exhaustion, say 10 stair repeats and add two more. At some point the “two more” become the norm, it feels automatic. If it’s 95 degrees out I do another flip. Rather than the reasonable seemingly healthy choice of skipping hill work I do it mid-day, when it is hottest. Over time, that becomes the new norm. When confronted with a race in a hot building there is no shock to my body. As hot as a stairwell can get it rarely reaches 95 degrees, so the 80 degrees is not a shock. The hill I use to train on is steep, too steep to safely run down or even walk quickly. There are no stairs I would encounter in a race as steep as the hill. When confronted with an odd-ball building with stairs the angle of bleachers, it’s business as usual. I recall an old war movie with a submarine in crisis nearing the crush point as it plunged to the bottom of the ocean. As the crew feverishly tried to start the engines the commander called a fire drill! His reasoning…”that’s the perfect time to call a drill…that’s when fires happen…when all sh**t has broken loose”. From that time on any fire emergency will pale in the stress level compared to that drill…the crew has a new norm.
We are talking about mind training as much as body training. The risk, of course, is over-training. One is essentially on a razors edge. If you push the body beyond its ability to handle the stress it will break down. If you just nudge the needle almost at but not on the breaking point, the body and mind learns the new norm.
This is also good news for all of us as we get older. So much focus is placed on the loss of muscle fiber, the drop in blood ejection factor of the heart, the drop in ability to use oxygen. These are inevitable, but the brain has a role in physical performance unless we chose to believe all the dire warnings of reduced performance. Could it be that our drop in performance as we age is largely due to mis-belief? You achieve what you believe!