Has Endure by Alex Hutchinson been sitting on your reading list? Pick up the key ideas in the book with this quick summary. Most people can conjure up a vivid scene of a marathon runner crossing the finish line only to collapse to the ground, visibly shaking, covered in sweat, and barely able to function. When you witness these scenes, it’s easy to ask yourself, “How did they make it over the line? What kept them from collapsing a few minutes earlier?” These are questions that the author, Alex Hutchinson, asked himself, ever since his grad-student days when he ran for the Canadian national team. Since then, Hutchinson has become an expert on endurance sports and has been able to discover how it is that human beings are able to push their bodies to the limit, climb to the top of the highest mountains, and cross those seemingly insurmountable boundaries of pain and effort. Along the way, Hutchinson has unearthed intriguing scientific facts concerning just how far we’ve come in understanding the biology of endurance, especially as it pertains to the brain. Recent research has shown that the mind actually plays a very large instinctual role in sending signals to the body about when to pace itself and, on the contrary, when to shut down. As Hutchinson has discovered, something that might seen incredibly uncomplicated, such as running or riding a bike, in fact, is a fascinatingly complex process. In this book summary, you’ll discover In this summary of Endure by Alex Hutchinson will explain:

• what we can learn about marathon runners from eleven-year-olds;
• why thinking too hard can affect your performance in an intense competition; and
• why hosting a marathon at the Dead Sea would likely produce record-breaking results.

Endure Key Idea #1: Testing the true limits of human endurance can result in fatal consequences.

British explorer Henry Worsley liked to push himself beyond the normal boundaries of human endurance. One of these boundary-pushing expeditions started in late 2015 when Worsley attempted to walk across Antarctica alone. Although he did travel very far on this expedition, the journey started to take a serious toll on his body after 56 days. On the night of the 56th day, he was hit with painful indigestion, which prevented him from getting any sleep. This meant that the following day, Worsley tried to rest, but he still had 200 miles still to go, and he couldn’t afford to take too much time off. At midnight, with the polar sun still beating down upon him, he resumed his journey, the leg he was on involving climbing up the Titan Dome – a mountain of ice that peaked at 3,100 meters above sea level. Every step of the way, Worsley faced strong headwinds which drove sheets of snow against him as he struggled to breathe in the thinning air. After 16 hours, Worsley had to stop for another break. Just in case he had to call for help during this solo journey, Worsley carried a satellite phone on him at all times. This was something of a double-edged sword: while the phone could save his life, it also gave him a bit of a security blanket in that he felt so safe being able to contact people that he was pushing his body past its limit. At this point, he’d already lost 48 pounds in bodyweight. Remarkably, even in the dire situation he was in, Worsley would last more than another week before he finally decided to use the phone to call his rescue team. By this point, he’d walked for 70 days and was just 30 miles away from his goal. The following day, his rescue team picked Worsley up and and flew him to a hospital in Punta Arenas, Chile, where he was quickly diagnosed with dehydration and exhaustion. However, that wasn’t the worst of it — the doctors also found signs of bacterial peritonitis, an abdominal infection that would require immediate surgery. Things quickly took a turn for the worse. Due to the weakened state of his body, Worsley was unable to fight the infection, and on January 24, 2016, his organs shut down, leading to his death. This tragedy raised some important questions about the ethical and practical limits of expeditions that would require such intense boundary-pushing. However, plenty of humans have safely returned from unbelievable destinations like this, and in the book summaries ahead, we’ll look at the human body’s limitations, and why some feats are possible, while others simply aren’t.

Endure Key Idea #2: Out of instinct, we pace ourselves so that we can give that final push in a long distance run.

While the author was working on his PhD, he ran on the Canadian national team for middle- and long-distance races for. Eventually, he realized that at the end of each race, he would run faster, even though that wasn’t part of his strategy. He then wondered whether this was everyone’s experience with running. In 2006, researchers Tim Noakes and Michael Lambert published a study that followed the world’s greatest long-distance runners. Their findings showed a consistent pattern: while the runners would start off fast, the best ones would end up decreasing in speed during the middle of the race, only to accelerate again before finishing. This happened consistently, even though one might assume that their energy would be depleted by the end of the race. A casual observer would probably see this is a strategic decision by the runners, but it’s likely an evolutionary response in our brain. Sports scientist Dominic Micklewright of the University of Essex wanted to learn more about our ability to pace ourselves, wondering whether it was an instinct that develops at a particular time in our lives. Micklewright’s curiosity was inspired by Swiss psychologist Jean Piaget, whose studies were based on how childhood development is made up of distinct behavioral phases. So, in 2012, while working with children from age five to 14, Micklewright had the goal of figuring out when exactly it is that we develop the ability to pace ourselves. He noticed that children ages eleven and under would sprint at the start and get slower and slower as the race went on, whereas children eleven and olderwould pace themselves the same way the world-record holders did, by slowing down in the middle of the race and finishing with a sprint. According to both Micklewright and fellow sports scientist Tim Noakes, this pacing pattern is not a strategy, but is actually an instinct engrained in the human brain. They draw parallels to our time as hunter-gatherers, and believe that it developed so that we could run long distances during a hunt while conserving energy, in case we needed to finish the hunt with a final burst of speed.

Endure Key Idea #3: Having a tired brain can affect how much you can endure physically.

In 2013, Samuele Marcora traveled over six and a half thousand miles by motorcycle. This journey was between London and Beijing, a test of his endurance that doubled as a continuation of his long-term study of the mental component of physical effort. His trip from the UK to China reinforced Marcora’s belief that the mind is a big component when it comes to how much human beings can endure. In other words, fatigue isn’t just a physiological experience. Prior to this, in 2009, Marcora conducted a study by having half of a group play a mentally challenging computer game for 90 minutes. The other half of the group were tasked with watching a pleasant 90-minute documentary, such as The History of Ferrari. At the end of these tasks, all participants were then asked to exercise on a stationary bicycle until they reached exhaustion. The participants who’d just watched television lasted, on average, 15.1 percent longer than those who’d played the computer game. The groups were physiologically similar to each other, so the results suggested that it was the mental fatigue of the complex computer game that caused the participants who’d played it to become exhausted sooner. This study also displays proof for the theory that says that perceived effort is a significant factor in endurance. People have been studying perceived effort since the 1960s, when Swedish psychologist, Gunnar Borg began his study and measure of this quality. Borg came up with a scale that went from six to twenty: six being the least perceived effort a person can display, and twenty being the most. What Borg found forced a complete reconsideration of what science understood of endurance at the time. Up until this point the body was treated like any other machine, meaning that it would continue functioning as long as the mechanics (in this case, the muscles) were operational. From this mechanistic view, exhaustion can only come from physical effort. Marcora’s model took Borg’s findings a step further: he states that an athlete’s total exhaustion is the combination of both muscle fatigue, which creates the initial feeling of mounting effort, and the person having reached their maximum threshold of perceived effort. The point where these two things intersect is where all effort must cease for that person. It makes a big difference to consider perceived effort, since it has to do with a lot of different mental factors, such as how motivated a person is and any subliminal messages they may be picking up on.

Endure Key Idea #4: Athletes have a higher-than-normal pain tolerance, which leads to better performance.

Veteran cyclist Jens Voigt has worn the Tour de France yellow jersey twice, symbolizing that he’d taken the lead in the famous race. However, he is also known for his love of physical suffering, which, as he puts it, is just a weakness to overcome. While this view might sound extreme, there are many athletes who would agree. It’s also important to note that it may just be an athlete’s willingness to suffer physically that leads to the fact that athletes simply have a higher pain threshold than the average person. One of the first studies of athletes’ perception of pain was conducted in 1981 by psychologist Karel Gijsbers, who compared the pain tolerance of elite swimmers to that of amateur swimmers. Dr. Gijsbers measured their pain by using a blood-pressure monitor to stop the blood circulation in the participant’s arm. While this was happening, the participants were told to clench and open their fist once per second. Gijsbers was able to mark their pain threshold as the moment when they first reported pain, the maximum tolerance being the instant they asked to stop. While the pain tolerance of all participants was similar, the elite swimmers could continue contracting fists for far longer than the amateur ones. On average, the hobbyists could make 89 fists while the athletes could make 132. Now the question is, why can athletes endure so much more pain? Subsequent studies by Dr. Gijsbers suggest that it is due to training. By testing athletes throughout their swim season, Gijsbers was able to find that overall, the pain tolerance was at its highest when their training was at its peak, which was during the month of June. This isn’t the only proof of this: a related study from Oxford Brookes University shows that increased pain tolerance is correlated with increased athletic performance. It was even evident that athletes who trained with short sections of high intensity, and therefore high pain, progressed more than those who trained for longer periods of less intensity. Therefore, the more pain tolerance an athlete endures during training, the more benefits they’ll experience in their performance. However, an ability to tolerate pain is only one factor of good athletic performance, as we’ll discover in the next book summary.

Endure Key Idea #5: Athletic performance greatly relies on oxygen intake.

All athletes can attest that a good coach is one of the best things for their performance, and if there’s one piece of advice that every coach will give, it’s to breathe, breathe, breathe. Breathing is essential to anyone’s athletic performance, as oxygen intake has a direct influence on an athlete’s abilities. During training, athletes can measure their maximum oxygen intake through what is known as VO₂max, which stands for volume, oxygen, maximum. Basically, the more oxygen a person is able to take in, and therefore circulate through their body, the better they’ll perform – especially in endurance sports like marathon running. It wasn’t by chance that Norway’s Bjorn Daehlie not only won multiple cross-country skiing awards in the 1990s, but also held the record for the highest VO₂max ever measured. Daehlie topped out at 96 milliliters of oxygen per kilogram of body mass per minute. The average human capacity is 35 ml/kg/min, so this is a massive, record breaking amount. Of course, VO₂max isn’t the only indicator of athletic performance. Another Norwegian athlete, Oskar Svendsen, beat Daehlie’s record with a VO₂max of 97.5 ml/kg/min. However, because Svendsen was a cyclist, he retired early after a spotty career. The ability to intake oxygen is also the reason why athletes perform better at lower altitudes. At lower elevations, there is simply more oxygen available. Canberra University in Australia is located at an elevation of 577 meters above sea level. According to the school’s own study, this elevation significantly reduced the VO₂max levels, causing the school’s runners to produce slower run times. Conversely, when runners experience an oxygen-rich atmosphere, they’re more likely to beat their own personal best and set new world records. Scientist Yannis Pitsiladis came up with the idea to host a marathon at the Dead Sea, 400 meters below sea level. His theory is that holding the event at such a low elevation could be the solution to having a runner finally overcome the challenge of finishing the race in less than two hours.

Endure Key Idea #6: Endurance is also affected by a person’s core body temperature.

Heat stroke is one of the most dangerous risky situations that athletes can find themselves in. It has shown how deadly it really is to both professionals and amateurs alike. Avoiding heat stroke is a huge reason athletes pay close attention to the overall temperature of their bodies, also known as their core temperature. But there is another link between heat and athleticism, which is that core body temperature actually influences an athlete’s endurance. More specifically, an athlete’s core body temperature is a good indicator of how much more they’ll be able to endure. The link between temperature and performance was the basis for a 1999 study by Copenhagen University’s José Gonzalez-Alonso. He closely studied seven athletes who he told to exercise on a stationary bike until they reached a point of exhaustion. Prior to exercising in this way, the athletes bathed for 30 minutes in water that was either 36, 37, or 38 degrees Celsius. In the end, the cyclists with a 36-degree core temperature lasted twice as long as those with a 38-degree core temperature. Overall, the study showed that every participant called it quits when their core temperature reached between 40.0 and 40.3 degrees. This exact study had a great influence on the 2004 Olympics in Athens, during which, coaches used cooling basins before a competition to bring down their athlete’s core temperature. Since then, research in this area has questioned which area affects core temperature the most: the brain or the stomach? In the 2008 Olympics, certain athletes were drinking ice slushies before competing, adhering to the fact that melting ice in the stomach has been found to lower core temperature by as much as 0.7 degrees Celsius. Doing this also seemed to give athletes the ability to push their core temperature slightly higher before they reached a point of exhaustion – around one-third of a degree more. What is the reasoning behind this? It’s believed that when athletes compete after drinking the ice slushy, the body is the first part to warm up, but the whole system won’t actually reach exhaustion until the brain reaches that critical temperature. The data behind this, though, is still inconclusive. It’s very possible that the temperature sensors in the stomach are the main influencer for the brain when it comes to shutdown, and drinking the slushy delays this signal. At the time of writing, neither hypothesis has yet been confirmed.

Endure Key Idea #7: Another way to improve athletic performance is through mindfulness and lowering stress levels.

Based on evidence already stated, we know that the mind plays a bigger role in physical endurance than sports scientists believed in previous generations. However, in the East, the power of the mind has always been seen as the center of athletic performance, especially in sports such as martial arts. It’s only in recent years that Western cultures have begun looking to Eastern influence of mindfulness for insights into achieving higher levels of endurance. We normally define mindfulness as giving all of our attention to any given action, and we can credit its introduction to Western training programs to German neuroscientist Martin Paulus. Dr. Paulus was especially interested in the influence mindfulness might have on soldiers. Dr. Paulus brought into Western lexicon the mindfulness concept of Zen Buddhism, as taught by Jon Kabat-Zinn, who developed a structured eight-week program aimed to lower stress levels. His belief was that lowering stress would keep soldiers calmer during stressful situations. A 2016 study involved Dr. Paulus testing his results on soldiers near San Diego, California. The soldiers involved in this study had their brain activity monitored via an MRI machine. While the soldiers were in the MRI machine, the oxygen levels given to the soldiers were altered in different ways, at times making it difficult to breathe. The results of this showed that the soldiers who had not had mindfulness training were more likely to panic when their oxygen levels decreased, which then led to a peak of activity in the stress-related insular cortexregion of the brain. Then, after spending eight weeks in mindfulness training, the soldiers did not show stress during this situation and their insular cortex remained stable. Because of this, there is hope for soldiers to cope better with stressors in the field through cultivating mindfulness. On top of that, there is already plenty of proof that mindfulness is effective when it comes to reducing symptoms of post-traumatic stress disorder. Dr. Paulus has worked to develop a special mindfulness program tailored to athletes. This has an emphasis on embracing pain, concentration, and self-compassion. The results of these mindfulness programs haven’t yet been measured, but the US Olympic BMX Team have reported improvements in their performance since starting the program. Their racing times have improved, and the athletes have reported a feeling of deeper consciousness and connection to their bodies during activities. Summary Pt 8: The insular and motor cortices are the areas of the brain that are the closest related to endurance. Everyone’s experienced feeling exhausted. However, not many people are aware of what the precise process is which causes us to hit a certain point that leads to a full-body shutdown. For decades, scientists have been studying exhaustion as a purely physically response, however, neuropsychologist Kai Lutz was the first to think that exhaustion might be something that comes from within the brain. He found that the regions of the brain that first recognize exhaustion are the insular cortex and then the motor cortex. Dr. Lutz discovered this through using EEG scans, or electroencephalography, which is a technique that tracks the brain’s electrical wave patterns. He studied cyclists pedaling at high speeds until they hit the wall of exhaustion around the 40-minute mark. Dr. Lutz observed that shortly before the cyclists gave up, the insular cortex was activated. The insular cortex is located at the center of the cerebral cortex and the brain itself. Right after it is activated, it was clear that a signal was then sent to the motor cortex, which is in charge of muscle control, resulting in the athletes calling it quits soon afterward. Since these are the two areas that anticipate the collapse of muscles from exhaustion, it is fair to call these two cortices the brain’s endurance center. However, it still isn’t quite clear how much control we can have over these areas of the brain. Dr. Lutz has found that we might be able to control and suppress the sensitivity of the neurons in the insular cortex, which would allow you to delay the message to the motor cortex and therefore, the muscles. This was tested in 2015 by another neurophysiologist: Alexandre Okano of the University of Rio Grande. In Dr. Okano’s study, he hooked cyclists up to electrodes that would directly activate the insular cortex via transcranial direct-current stimulation. After 20 minutes of this stimulation, the cyclists improved their racing times by around 4 percent before reaching exhaustion. Another theory is that continually stimulating the neurons of the motor cortex would effectively block the signal from the insular cortex. This might sound like a promising theory, but it hasn’t yet been proven successful. The practice of transcranial direct-current stimulation is still in its rudimentary stages. Scientists studying this are thus far unable to deliver this stimulation with pinpoint accuracy. By targeting the motor cortex with this stimulation, other parts of the brain are affected, including the insular cortex. Nevertheless, it’s been shown through these studies that progress has been made toward understanding human endurance, although there is still a long way to go before we have complete control.

In Review: Endure Book Summary

The key message in this book summary: Endurance as a human phenomenon involving far more than just muscle power. There are actually  many physiological elements at play, from core body temperature to oxygen intake, as well as other psychological factors, such as perceived effort and pain tolerance. Each of these factors are significant in the level of athletic performance humans are capable of, especially in terms of setting new world records in sports like marathon running, cross-country skiing, and other feats of endurance. Actionable advice: If a method works, use it, even if evidence suggests it’s nothing more than a placebo. Nearly every athlete will attest to faster recovery if they bathe in ice after a competition. However, studies show that this practice doesn’t actually decrease inflammation levels, the thing the baths are intended to reduce. The thing is though, if there’s a method that helps you recover, even if it’s purely psychological, it’s valuable to use it because sometimes belief is just as influential as science.