EVERFIT book review - ENDURE

Book Reviews, May 08, 2018

Alex Hutchinson's new book "ENDURE- Mind, body, and the Curiously Elastic Limits of Human Performance" is a must read for every coach, and athlete wanting to improve.

Alex (PhD) is a writer for Outside magazine, a past columnist for runners world, and writes for the New York Times. He is a runner, in fact a VERY good runner (two time finalist in the 1500m at the Canadian Olympic Trials). He has gained a PhD in physics from Cambridge, and has worked as a researcher for the US national security agency. 

The book is divided into Part One - Mind and Muscle, and Part Two - Limits with sections on Pain, Muscle, Oxygen, Heat, Thirst, and Fuel. Interspersed throughout the book is stories from his own running career, and also some fantastic insights of the Nike Sub 2 project where Alex was lucky enough to be part of the press gallery that had access to the build up and sub 2 event in Italy. 


Following is some brief notes from the book for my own benefit. Please get hold of this book to further your own education on expanding your ability to be better, to be EVERFIT.
Alex starts out stating something that I have come to fully appreciate over the last few years as a coach and athlete - "the brain and body are fundamentally intertwined and to understand what defines your limits you can't separate them".  In the first section of the book he goes over the Antarctic missions by Shakleton and Scott "the greatest human performance of sustained physical endurance of all time". In the early days of athletic measurement it was thought that human systems were machine like whose energy expenditure could be closely monitored and explained. As time has gone on the the importance of seemingly immeasurable factors such as certain psychological components has creeped in to muddy the waters of endurance predictability. As Michael Joyner (researcher at the Mayo clinic, and predictor that a best a human could run the marathon would be 1hr 57min and 58sec) states - "our level of knowledge about the determinants of human performance is inadequate". Alex unpacks Prof. Noakes work on the brain centered "Central Governor Theory", that is the brain has the final say in putting in endurance limits as a safety mechanism to stop us from literally dying. Noakes feels that sports physiologists overly focus on VO2 max producing a "brainless" model of exercise performance.  Pacing in racing isn't actually voluntary, the brain forces you to slow down long before you are in physiological distress. This can be crudely back up with the fact that an athlete using a brain altering drug like Tylenol will boost endurance without any apparent effect on the cardiovascular and muscular system. Also of the 66 world records in the 5 and 10,000m dating back to the 1920's the last km was either the fasted or second fastest (behind the opening k) in all bar one. This could show that the brain let's the "brake" off a little knowing the end is in sight? The debate is not if the brain plays a role in limiting endurance, the debate has shifted to how. 

Samuele Marcora (exercise scientist at the University of Kent's Endurance research group) has completed some fascinating research on how mental fatigue, and pictures of frowning faces (compared to joyous ones) can negatively effect your ability to exert effort. In one experiment the subjects that completed a mentally draining computer game gave up 15% sooner in a cycling test compared to the group that watched an emotionally neutral documentary. In another those that were shown happy faces rode for 3min longer and reported a lower sense of effort at certain time points. Seeing a smiling face in a race (even subliminally as in this experiment) promotes feelings of ease that permeate into your perception of your cycling or running intensity.  When brains are tired, or you see grumpy faces pedaling a bike simply feels harder.  In his view the decision to speed up, slow down, or quit is always voluntary, not forced on you by the failure of muscles. Fatigue ultimately resides in the brain. The chasm between psychology and exercise physiology is what Marcora was hoping to bridge when he spent his mid career sabbatical studying psychology.


"The decision to speed up, slow down, or quit is always voluntary, not forced on you by the failure of muscles."


The second part of the book started with discussing pain. Wolfgang Feund is a researcher is Germany that studies pain in athletes. His findings reinforce the idea that all else being equal the gold medal will go to the athlete who is willing to suffer a little more. Regular physical training with planned unpleasant high intensity workouts will increase your pain tolerance. Pain tolerance has been shown to be linked to the type of training you are doing. You can work on pain tolerance in many areas of life by learning to "accept" it and not blocking it out e.g during a deep tissue massage, hypoxic swim training, cold showers. Alex talks at length about he world one hour cycling record (now at 54.526km by Bradley Wiggins) which done right is "literally the longest bout of painful high intensity exercise you can endure."  I found the chapter on Muscle with the story of a man lifting a car off an injured pinned cyclist, fascinating. This display of "hysterical strength" demonstrates that under the right conditions we are all capable of much more than we expect. There is past history stories in World War Two where German soldiers using the early version of meth boosting "fighting endurance", and how recent studies have shown that amphetamine tablets increase strength by 13%. The power of the mind was also demonstrated with an hypnotic study when the hypnotist told one very skeptical subject he was touching him with a hot poker when it was a ball point pen, "the blister that appeared within the hour took a week to heal and served to convince the subject of the reality of hypnosis." I would have thought that the pounding the quads take during ultra events would be a major rate limiting factor but studies have shown that once you have been running for 24hrs leg musculature will be 35-40% weaker and they won't lose much more. Much of this is "central" reflecting either reduced output from the brain or loss in transmission from the spinal cord. Trying to make a clean divide between brain and muscle fatigue is impossible thou as they are inseparably linked - we have nerve fibers that send muscle condition info to the brain and we integrate this info without realising it.


There is no limit more fundamental to endurance sport and life than oxygen. The official world record for breath holding (static apnea) is 11min 35 sec. I learnt that the spleen holds a reservoir of oxygen rich red blood cells that can be deployed in emergencies. In the human body this can get released after the diaphragm involuntary contracts (due to the build up of CO2) offering a psychological boost and prolonging your breath hold. Alex talks about mountain climbing, and freediving in this section of the book. Another interesting fact I found out was that up until June 2016 there has been 7,646 summits of Everest by 4469 people with 197 of those being oxygen free. In comparison the 4min mile has been broken 4518 times (up to March 2018) by 1400 people. Vo2 max is a good predictor of performance but won't pick the winner from a pack of well matched athletes. The highest ever recorded was 97.5 ml/kg/min by a Norwegian cyclist Oskar Svendsen (who retired soon after winning the World time trial champs as a junior) 


Heat was the next discussion point touched on. Did you know at rest you have around 250mls of blood flowing through the vessels near your skin and are emitting around 100 W of heat radiation (from electromagnetic waves). When you are running at 16kph the blood vessels dilate dramatically to allow 8L of blood to flow and you produce 1500W of heat. Our bodies are very good at dealing with heat. When wanting to get used to hotter conditions studies have shown that 60-90min of moderate exercise in those conditions will produce rapid physiological changes within a few days with full acclimatization taking place within 2 weeks. Further studies conducted by Stephen Cheung (avid cyclocross racer and environmental physiologist at Brock Uni in Canada) showed that groups that were trained in "motivational self talk"  specifically tailored to exercising in heat (so suppressing negative talk and replacing with positive statements) could improve their cycling endurance testing from 8 to 11min and pushed their core temperature at the point of exhaustion by half a degree. this emphasized an important take away from this book..........


"The right frame of mind allows you to push beyond your usual limits.........even if you are fit you can still improve your performance with your perception."


The thirst chapter reinforced the importance of drinking to thirst and not overdrinking during an endurance event which causes "hyponatremia" or water intoxication.  Having a hydration plan that is individualised is important.  When Haile Gebrselassie surged to his new world record in the marathon of 2hrs 04min and 26 sec his sweet rate was 3.6 L per hour! On completion of his record run he had lost 10% of his body weight. When gastric emptying rarely exceeds 1.3L/hr you can see how some people will never be able to replace the fluid lost. A 2013 meta-analysis in the BMJ showed that any losses of less than 4% are very unlikely to impair (endurance performance) under real world conditions. In marathons the fastest finishers tend to be the most dehydrated. The most common reason people drop after finishing the marathon is a loss of blood pressure caused by blood pooling in the legs after you stop running. One of the most important points I drew from this chapter is that to perform at your optimum ensure you are properly hydrated before starting the race. 


Fueling the body incorrectly will limit endurance. A 1973 journal article by a Scottish Dr. reports the case of a 27 year old man who undertook a medically supervised fast in hospital. He lost 276 pounds over 382 days without eating. This shows that when you "bonk" in an endurance event your fuel tank isn't empty. It's not just how much fuel is in the tank - endurance performance is dependent on what types of fuel you have available, where it's stored, and how quickly you can access it.  The more cardiovascular fit you are the greater proportion of fat you burn at any given speed. The burning of carbohydrates (CHO)dominate for intense exercise - one study showed that running at 2hr 45min pace for the marathon relied on 97% CHO fuel while slowing down to 3hr 45min pace reduced the CHO mix to 68%. The liver can store 4-500kcal of glycogen compared to around 2000 kcal for fully loaded leg muscles. The reason we eat a pre race breakfast is to restore the liver glycogen as it gets depleted overnight due to fueling your "energy hungry" brain during sleep.  Kenyan runners (who hold 60 of the top 100 marathon times) typically get 76% of their kcal from CHO. Another 35 times on the top 100 are held by Ethiopians who get 64% of their kcal from CHO - if there is a better diet plan for marathon endurance no one has told the best endurance athletes in the world. Using a high fat/low carb diet (this is popular at present) will help with burning fat but athletes lose some of their ability to harness quick burning CHO for short sprints. This results in a "severe restriction on the ability of subjects to do anaerobic work." Trent Stellingwerff has shown that high fat diets don't just ramp up fat burning - they "throttle" CHO usage by decreasing the activity of a key enzyme pyruvate dehydroganase.  Scientists have figured out the maximum amount you can absorb during exercise is 60 grms (250kcal) per hour. The rate limiting factor is the absorption of CHO from the intestine into the bloodstream. There is data showing that if you combine two different types of CHO (glucose and Fructose for example) they will pass through the intestinal wall using two different cellular routes that work simultaneously, meaning you can absorb as much as 90 grms of CHO per hour. The glucose - fructose mix is now standard in most sports drinks. Researches in Scandinavia have shown that glycogen stores in muscles are not just energy stored they also help the individual muscle fibres contract efficiently - meaning your leg muscles will "weaken" as you burn through your glycogen stores. So your maximum speed gauge is intrinsically linked to your fuel gauge, and the body will preferentially burn your stored muscle glycogen rather than glucose from the blood stream.  Of course with very long ultra type events anything that decreases your dependence on external CHO sources and allows you to tap into your stored fat stores has the potential to help decrease your chance of bonking and mean you don't have to carry as much fuel. Even the high fat/low carb ultra runners like Zach Bitter and Timothy Olsen ramp up CHO intake before and during long training runs and races. Olsen for example eats sweet potato the night before and takes one to two gels per hour (100kcal of CHO) during races. Dave 
Zabriskie (Tour de France cyclist) statement on the LCHF diet "For long easy training it's good. For day after day racing like the Tour, you have to eat the carbs." 

What I got out of all the information in the Fueling chapter that a LCHF way of eating has a place if you are training for an Ultra or a double Ironman where you want to really hone your body to tap into your fat reserves more efficiently and you don't want to carry excessive weight in extra food, and you are planning on that "diesel" turn over without having to rely on a finishing sprint or wanting to burn candles with increased pace during the event. The fact that no high level marathon runner sticks with a HFLC diet tells me that it could be as good as BUT isn't better than a conventional plant based whole food approach with CHO as the main fuel source. I am now also going to use 1-2 gels on my half marathon races as it might improve leg musculature to remain efficient if they don't empty the stored glycogen as quickly. 


One of the last chapters is "Training the Brain". One of Tim Noakes former students Ross Tucker talks about pacing. In his formulation he describes pacing as "the process of comparing the effort you feel at any given point in a race to the effort you expect at that stage - an internal template that you develop and fine tune from experience." Anything that moves the effort dial in your head up or down will have an effect on your endurance even if it doesn't effect your muscles, heart, or VO2 max. So caffeine, smiling faces, motivational cues, and positive self talk can ALL help your ability to go longer faster. Training is not about expanding the capabilities of the muscles, and heart, but it recalibrates the brains horizons. An Olympic athlete is fit and strong but none of that matters if they are not resilient - capable of shaking off setbacks and adapting to unexpected circumstances. Learning to monitor how the body actually feels without layering on negative past experiences is very important. This is where meditation can be useful to hone in on the present and to dial down past experience, or future ramifications. Embrace rather than avoid pain, and address pitfalls like perfectionism by teaching self compassion. 


"Training is not about expanding the capabilities of the muscles, and heart, but it recalibrates the brains horizons."