Alex Hutchinson is an award winning endurance sports journalist and author, who you may know from his column Sweat Science. His new book Endure explores human endurance performance limits, real and perceived, and how to push them further and further. 

• How there is (almost) always a reserve of resources to tap into, even when it feels like you're working at your absolute full capacity.
• The similarities and differences between different models (the psychobiological model by Samuele Marcora and Central Governor model by Tim Noakes) of how the mind imposes limits on the body.
• How endurance performance is "elastically limited" by pain, muscle, oxygen, heat, thirst and fuel. 
• Brain endurance training and brain stimulation for improving endurance performance.
• Alex's top practical tips for how to push closer to your true limits. 

0:24 - 

• Alex is an award winning journalist and author.
• He is the guy behind the popular 'Sweat Science' column that is now in Outside magazine, previously on Runners World.
• His new book has just been released: Endure. Mind, Body and the Curious Elasticity of Human Performance.

4:00 -

• The basic question it tries to answer is 'what defines the limits of endurance?', under various contexts.
• If you can answer this question you have a better chance of changing these limits.
• The biggest takeaway from the book is how important the brain is in dictating limits that feel very physical to us.
• Limits that feel physical, such as being out of breath and the burning in your legs, are ultimately mediated by the brain.
• Limits are negotiable as a result.
• I also hope readers will take away some great stories to share on their next long run or ride. 

7:20 - 

• I started out as a journalist, having previously come from a physicist background, but wanting to write about things I cared about.
• I began writing about the science of endurance and evolved a particular interest in the brain and its role in endurance.
• I had an unusual race experience at 20 years old. I was a middle distance runner (1500m) and my mission was to break 4 minutes for the 1500. I had been stuck at the same level for 4 years despite training at a higher level. Then one day I had a bizarre race on a crappy track at a crappy meet where the timekeeper read out the wrong splits to me and misled me into thinking I was having an amazing race and running way faster than normal. This has the result of tricking me into thinking this was my race, so I really went for it and improved my best time by 9 seconds (4.01 to 3.52). In my next race I ran three seconds faster than that, and the following race another 5 seconds, all of which seemed to be triggered by the misunderstanding. Since that moment I've known it's more than just physiology that helps get the most out of yourself, and I'm still chasing that.
• The book is split into three parts:
  
  • Explaining the different hypotheses of the mind's and muscles' role in endurance performance.
  • Factors that impose limits, both real and bendable, on endurance performance (e.g. hunger, heat).
  • Limit breakers.

11:00 - 

• Two different hypotheses: the central governor model proposed by Tim Noakes and the psychobiological model by Professor Samuele Marcora.
• Tim Noakes argues the brain is wired in a way to anticipate danger and protect you from it, so it won't let you run yourself to the point that your heart or brain will run out of oxygen.
  • Your brain will unconsciously impose limits. As you get tired, it recruits less muscle and won't let you push as hard as you want to because your brain is worried you're in danger.
  • You're able to sprint finish in a race because once you've seen the finish line your brain is now aware you aren't actually in danger.
• Samele Marcora argues that there's no unconscious central governor holding you back for your own protection, but it comes down to effort and motivation.
  • Ultimately the decision to slow down or stop is just because the effort is harder than you're willing to tolerate in that moment – you're breathing is laboured, metabolites are accumulating in your muscles etc.
  • Every exercise failure is a conscious decision.
  • Based on this hypothesis you might suggest that being able to sprint to the finish line is the result of reconceptualising how hard it actually is because the end is in sight.
• Both hypotheses agree that the brain is what ultimately makes the decision about limits, but they differ on whether that decision is conscious or unconscious, and whether it's anticipating in advance or responding in real time.
• These hypotheses are still disputed by some researchers, who argue that it is purely physiological.
  • Following the 'Breaking2' project, Andy Jones at the University of Exeter who was a lead scientist with Nike on the project and has also worked with Paula Radcliffe, would argue that you can evaluate someone in a lab and predict how they will perform based on their physiological measurements (VO2 max, lactate threshold, and economy).
• Everyone knows motivation matters, and the mind is not irrelevant, but some may dispute the idea of a central governor and argue that if you want to run a faster marathon it's about tweaking the parameters of your body like a machine.
• Personally I don't know yet which hypotheses I believe. I often change my mind after speaking to different scientists.
  • On a logical basis and based on the evidence and the simplicity of the model, I like the psychobiological model – it's a balance between effort and motivation, and effort is dictated by what's going on in the body.
  • However intuitively, particularly when I race, the central governor just feels right. It feels like there's something unconscious, a distortion of my physical limits that is released when I get to the finish line.
• If you read deeper into each of the models, the differences between the models start to seem a little less stark, and are actually fundamentally about the same thing.
• What Ross Tucker (Noake's former student) has argued is that the central governor anticipates your needs through the sense of effort. In this case both models would converge on the idea that your sense of effort is the final arbitrator.
• Steven Chung always says "science is a human endevour" - people have stakes in their theories and understandably want credit for their work, so sometimes the debates get personal.
• From a logical perspective Mikael also likes the psychobiological model.
  • Research mentioned in the Endure book discussed a study where people were put on stationary bikes and shown a screen which flashed up (very briefly, unconsciously seen) to the cyclist and they found those shown smiling faces did better on the time to exhaustion test. The central governor model might find this difficult to explain.

21:30 - 

• The book discusses 6 possible limits: pain, muscle, oxygen, heat, thirst, fuel.
• If you believe the brain theories of endurance you could argue that these all mix together – they're acting on the same ultimate limit which is your sense of effort or something like that.
• These are real physical limits that no amount of psychological skills training is going to allow you to get over them. E.g. If I put you in a room with no oxygen, you would die.
• The question is to what extent are they real limits in the way that we experience them?
  • If you take someone who is not a habitual exerciser and get them to start running, they'll usually stop and tell you something like: "I had to stop because I was really out of breath". "Okay so why did you have to stop?" "Because I was really out of breath" "Okay but why didn't you just keep running?" You have a difficult conversation between something that's making you want to stop, and something that's forcing you to stop.
• Oxygen is a great example of this. I always ask people what do you think is the world record for longest breath hold? I was astounded that the official record is 11 minutes and 35 seconds.
• How is it that some people can hold their breath for that long but most of us feel like we can't hold our breath for more than a couple of minutes?
  • If you hold your breath, after a couple of minutes you'll start getting involuntary contractions of your breathing muscles – basically your body has decided that your brain is crazy for trying to hold its breath and it's forcing you to breath by doing it on its own, which is when most of us break our breath hold.
  • It's not because you're out of oxygen, it's because carbon dioxide levels are rising in your blood and it triggers a warning signal that forces you to try and breathe.
  • Free divers can learn to ignore that signal. They suppress the breathing contractions and keep holding their breath until the oxygen levels in their blood reach about 30mm of mercury which is roughly the level required to sustain consciousness. They are capable of continuing to hold their breath until they pass out, which is why free diving is so dangerous – if you pass out underwater you'll drown.
• So while it feels like holding your breath for 2 minutes is a serious physical limit, there are other people saying it's not a physical limit and can be extended to 11 minutes. They have learnt the difference between the warning signal and the actual physical limit.
• That kind of pattern occurs for a lot of these limits – the feeling that you can't go on comes far before the actual physical brick wall.
• The book discusses pain as a limit, and research shows that when people measure pain threshold and pain tolerance in endurance athletes compared to sedentary individuals, the pain threshold is similar but endurance athletes tend to have a much higher pain tolerance.
  • Endurance athletes feel the pain, and get those signals, but they are able to push through and tolerate it.
  • The basic theory behind this comes down to psychological coping skills, e.g. learning to distract yourself from the pain, or reframing it and removing the emotional component (e.g. not scared of the pain anymore).
• The same is true for things like thirst.
  • People who have been running for a long time often laugh at the idea of doing a half hour run with a belt full of water bottles. They know that you're just going to get thirsty and you won't pass out.
  • But for people inexperienced with exercise, they don't know that being thirsty doesn't mean that you're going to keel over indefinitely. They have fear attached to the signal.
  • Once you can just interpret it as a signal, it helps you to push farther.
• I think this is an under-appreciated part of people getting into shape and becoming better athletes.
  • If you train for a year, not only will you be a lot fitter but you'll be able to tolerate a lot more discomfort.
• There's the old debate of who suffers more – a 2 hour marathoner, or a 4 hour marathoner. Some argue the 4-hour marathoner is pushing their limits for 2 extra hours. However the experienced athlete who's been training for a long time has learned to hold their finger in the flame for longer, and closer to the flame. So in general, someone who's running a 2-hour marathon is able to make themselves suffer to a greater extent that someone who is more of a casual running who hasn't actually gone through that experience of learning to push through their warning signals.
• Related listening: Running, Peaking, and Suffering with Olympic gold-medal coach Malcolm Brown | EP#96

30:14 - 

• If you want to get faster at triathlon the first thing you can do is get better at running, swimming and biking – that's the easiest thing! Dealing with the brain is the icing on the cake.
• The interesting thing about trying to manipulate the brain is that it's independent of all the things you're probably doing in physical training.
• Samuele Marcora has been working for a couple of years on something he calls 'brain endurance training'. He's identified some of the aspects of cognitive fatigue that are associated with endurance performance.
• You need to have good response inhibition – which is the kind of thing that allows you to ace the marshmallow test where someone offers you one marshmallow now or two marshmallows later. Good endurance athletes are the ones who when they were four years old were able to say "yeah I'll wait and take the two later".
• There are ways of taxing specific cognitive traits, Marcora uses computer tasks where letters or numbers flash on the screen and you press a button corresponding to the specific pattern. It's not hard but it requires a lot of concentration, and is mentally fatiguing.
• The idea is that if you do this over and over again your brain will physiologically adapt to become more resistant to this kind of mental fatigue, which should be able to transfer into physical tasks.
• For example, when you go and try to run for an hour at threshold pace, you should find it a little bit easier because running at threshold pace is fundamentally a challenge to your ability to stay focused and to keep pushing yourself.  
• There are other approaches that I talk about in the book such as mindfulness based approaches to enhance athletic performance and endurance.
• The general picture is that these are intriguing examples but they're not full validated yet so when people ask me "Should I/how can I do this?" my general advice is that it's interesting stuff but it's a big time commitment for something that is not yet validated.
• I tried a 12-week brain training programme before a marathon and it takes time. Before you invest that time and effort you want to make sure it's validated and working.
• But everyone has a different risk-reward ratio and some people like the idea of being early reward adopters, understanding that it may not be validated yet and may turn out not to be optimal.
• I don't want to give the impression that this has been proved, the idea is out there but right now it's still a hypothesis and it's really difficult to test. I'm excited to see the research, but I wouldn't be out there trying to use it in my next race just yet.

34:50 - 

• The basic idea: if you take a 9-volt battery, attach a couple of wires to it, stick a couple of electrodes on your head and run a very weak electric current through your brain you'll change the excitability of the neurons on the path where the current is flowing.
  • You're not making them fire, but you're making them a little easier or a little harder to fire.
• As you get tired, the signals from your motor cortex get weaker, so even though you think you're pushing as hard the brain is sending slightly weaker signals to the muscles.
  • If you stimulate the right area, for example the motor cortex, the hope is that you can enhance the excitability of that area of your brain and then maybe you'll be able to maintain your effort for a little bit longer or make it feel a little easier and thus more sustainable.
• The first study I was aware of showing that brain stimulation can enhance endurance was back in 2013 and there's since been a lot of interest in the area.
  • There's a company in California that is now selling headphones that do brain stimulation.
• There have been a bunch of professional athletes who have tried it, and there have been triathletes in Kona who were sponsored by Halo Neuroscience (the Californian company).
• The evidence has been really mixed as other studies have tried to replicate these results. In the last few months there's been research from the University of Kent that clarifies some of the issues and methodological problems from previous studies.
• Now I'm starting to think this is going to be a real effect, and brain stimulation is going to have the ability to enhance endurance.
  • We will then need to have some serious conversations about whether it's something that should be restricted in athletic competition and what the long-term effects are etc.
  • To my knowledge there isn't any way of testing for evidence of brain stimulation, which complicates potentially banning it from competition, but doesn't exclude the possibility.
    • Another comparable example is baking sode. When I was an athlete in the 90's, baking soda was not a restricted substance – you can't ban sodium bicarbonate completely because you'd be banning things like muffins, but they said it's a restricted technique, you can't do soda loading. They knew they couldn't test for it but they just said don't do it.
    • They ended up changing that rule in the early 2000s partly because they realised that if you can't test for it you're just giving an advantage to people who are willing to be unethical. Maybe the same thing will be true for brain stimulation.

39:48 - 

• Throughout the book the Breaking2 project is discussed, where Nike and 3 top marathoners including Eliud Kipchoge were trying to break 2 hours for a marathon. It was very close, 2:00:25.
• As far as I know, they did not have a sports psychologist or anyone explicitly working on the brain which in some ways is surprising.
• Eliud Kipchoge in particular is a "mental master" - he exudes confidence and belief.
  • He was often interviewed asking how he was going to get faster (to go from 2:03 to 2:00) and he would reply that "the training is going to be the same but my mind is going to be different" or "the difference between you and me is that I believe it's possible".
• I came away from the experience of Breaking2 thinking maybe there's nothing a sports psychologist can teach Eliud Kipchoge, but maybe there's something the rest of us should be trying to learn from him.
  • This is the kind of thing sports psychologists are helping us to develop – some people are born, or for whatever reason acquire, really amazing mental skills and the rest of us should be trying to emulate or figure out what it is.
• It wasn't necessarily something they did, but they got lucky having someone like Eliud Kipchoge who has this incredible self-possession and self-belief.
  • To be bold and run the first half of the marathon in one hour and then keep going is a scary thing for anyone who knows how that's going to feel. It took someone bold, someone very special to be able to do that and not freak out.
• Nike deployed a lot of science, trying to do everything they could think of how to optimise this marathon. Some of the stuff they did was explicitly designed to help foster belief in the athletes.
  • For example drafting: They had done the calculations to tell them that drafting was going to be a significant benefit - if they could get the athletes to run in a really tight formation they'd be able to get more of a benefit than people had previously realised.
  • They had done a lot of sophisticated modelling and wind tunnel tests to determine what the optimal draft formation would be, but they also hand-built a body mounted wind detector that runners could mount on their chest to get real-time feedback on how much air resistance they were experiencing.
  • They flew out to Kenya and to Ethiopia and Spain, and had the athletes wear the body mounted wind detector and testing various different positions so the athletes could understand and experience why they were doing it, rather than just being told.
  • They really tried very hard to get the athletes to not just follow orders but be full participants in what they were doing and why it would help them. Athlete belief was really important.
• They didn't give the athletes a Nike training plan, they allowed them to work with their own coaches. Kipchoge has been working with Patrick Sang since he was a teenager and they have a very close relationship, total trust.
  • When I asked Kipchoge about his training and what he was going to do to run 2 hours, he said he was going to do whatever his coach told him to do.
• Personally when I was an athlete I always questioned and wanted to know why I was doing particular sessions and for me it was helpful in some ways but in other ways it causes me to overthink things.
  • I had friends or training partners who were much more "tell me what to do and I'll do it".
  • Increasingly over time I've come to believe that it's important to have a good training plan, but once you've chosen one you need to just put your faith in it and not be constantly second guessing it.

48:42 - 

• What is your favourite book, blog or resource?
  • Once a runner by John L Parker Jr
• What is your favourite piece of gear or equipment?
  • The single biggest impact on my running was a pair of big fleece mittons that look like boxing gloves - I have terrible circulation!

• Who is somebody in endurance sports who admire and look up to?
  • David Epstein who is the author of The Sports Gene. He wrote a science of sports book that was really nuanced and complex and it still sold well! So I'm hoping to emulate all aspects of that. 

Links and resources mentioned

• Brain training and psychobiology of endurance performance with professor Samuele Marcora | EP#17
• Psychology and the Central Governor Model with professor Tim Noakes | EP#43
• Running, Peaking, and Suffering with Olympic gold-medal coach Malcolm Brown | EP#96
• Endure: Mind, Body and the Curiously Elastic Limits of Human Performance
​

Connect with Alex Hutchinson

• On his website
• On Twitter: @sweatscience

Connect with host Mikael Eriksson

Hi! I'm your host Mikael,

I am a full-time triathlon coach and an ambitious age-group triathlete. My goal is podium at the Finnish national championships within the next few years.

I first started the website Scientific Triathlon in autumn 2015 as a passion project to share my learnings with a larger triathlon audience. Later on, in early 2017 I started the podcast That Triathlon Show. 

I sincerely want you to contact me to

• Send me feedback
• Give constructive critic​ism 
• Request topics and guests for the podcast
• Send me your triathlon-related questions 
• Tell me that you've rated and reviewed That Triathlon Show so I can give you a shout-out on the show and tell you how much it means to me!