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Limits of the Body

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Jad and Robert talk to two Ironman competitors, Julie Moss and Wendy Ingraham to find out how they do what they do. Physiologist Dr. David Jones tells us how to trick the voice in your head that tells you you're exhausted. Then we follow two men, Patrick Autissier and Jure Robic, as they bike across the country as fast as they can in a crazy race called The Ride Across America. Producer Lulu Miller brings us their story and New York Times writer Daniel Coyle walks us through the process of physical and mental breakdown RAAM competitors face.

Comments [45]

Steven_Stilly from Christchurch School

Overall, Great Job Radio Lab!! This podcast held my attention for the whole hour and kept me asking questions as I was listening! I found the section of limits of the body the most interesting because of the interesting ideas that were discussed in that part or the Podcast. I found it really interesting when Julie Moss said that there is no limits for the human body. I am not sure if I truly agree with this statement. There has to be a point where the body can't handle something no matter how much your mind is forcing you to keep pushing. If there is a limit to what the body can do than what is it? It is obviously more than we think. The limits of our body are almost like a paradox. For each person, it seems to be different. Each person has a different drive and motivation thus everyone has a different limitation to what they can physically do.

Oct. 20 2016 01:16 PM

When Julie Moss said she did not believe that the human body had any limits, I thought she was kidding. Surely, the human body simply stops functioning after being pushed past a certain threshold. However, Moss might have a point. Fifty years ago, the idea of free diving 100 feet deep seemed ludicrous. Boyle’s law suggested that a dive of that depth would be suicidal. Today, the world record free dive is 830 feet. While ancient Greeks postulated that no man could go longer than 4 days without sleep, Randy Gardner stayed awake, without stimulants of any kind, for a world record of 11 days and 24 minutes with no long term psychological or physical effects. Ultimately, while the human body might have a finite limit for its physical capabilities in every discipline, it is very likely that no human has even gotten close. One-hundred years from now people might laugh at the idea that world record free dive was only 830 feet and that only doing an Iron Man was considered a challenge.

Oct. 12 2016 08:56 AM
The Harold Brainard Pressley IV

It is, to me, very fascinating how our brain has a cruel system of tricking us into thinking that we need rest. It does this to keep us safe, however their is a way of tricking it into thinking that you are safe and manipulating it to give you rare boosts of energy. Noe, humans, figuring out a way to manipulate their own brain is one intriguing topic. As an athlete, my muscles stop at times and can not go any further no matter what kind of determination I have. I want to develop this way of tricking myself. Now this is all a paradox, because we have no idea what could happen if our brains had no governing power up there and instead let us use all of our stored energy at the same efficiently the whole time. This means that we could be running and our brains runs out of the energy that it should have stored and there you go from having full out energy, to none. What would happen? Would you just collapse and have to wait for someone to find you or wait for your body to replenish what it had just lost. No one knows, and the fact that the bike rider who won the race across America, forced himself to make his brain realize that he needed that hidden source of energy to keep going and keep going faster is incredible. As mind boggling as it is, it is something I would want to research and maybe have the ambition to come up with a substance that reveals this aspect to average athletes that do not know how to get pass the seemingly destructible wall..

Oct. 12 2016 12:31 AM
Alan He from Christchurch, VA

This is so fascinating to me that human body can actually push that hard and finish this almost impossible competition and biking. It is a very impressive podcast. I have only experienced have taste of blood in my throat after a long run or work out and “that was my limit” as I used to think. But now, I start to question myself, “ Is it really my limit? Can I go further?” My guesses, based on this podcast, would be “Yes”. The brain was probably lying to me all the time. In the meanwhile, if I could somehow keep producing food or energy to my body and dehydrate well, does that mean my body doesn’t have a limit and it can be “unlimited”? Corresponding to Calculus, if a variable is approaching to the limit of a number, it will never get to the number; does that mean we can always approaching to the limit of our body, but in reality we can’t? If then, what in the world is the maximum point our body can reach?

Oct. 11 2016 11:35 PM

I am amazed to imagine a world that everyone do not have a limit for their body. We can do all things. We do not need plane to travel around. Beside, we can jump around to the destiny. We can do so many things without the technology that tried so hard to make us have more ability. I want to see how we can go to a world like that.

Oct. 11 2016 09:38 PM

As a relativist, I do believe there is a limit of the body. The Radio lab illustrates the story of Julie who reached almost the limit of the body, with her strong spirit, she was able to move continuously. However, the strong mental status could not explain the body itself is unlimited because it's not the only the mental through that keeps body unbounded, but how the body challenge itself. For example, to choke one's self will not make one dies, and it does not explain the body is unlimited because the action shut down for the body's instinct. However, if we change the action from choking oneself to let one gets into the water, after one hour, and one loss all the air, he or she will "stop breathing", then, will the strong spirit wake up the person by itself? Not possible, because the body already died. Does the spirit keep the body unlimited? I think it's a good question but not the right question to ask, there is certainly a limit of a body, so as everything else, and we don't get it yet. But with discovering and resetting, we would find the "limit" that we recognize as now, and after that, there will be new "limits" that is outside of the space we experience now.

Oct. 11 2016 02:38 AM

I felt really depressed when I heard about Julie Moss’s story. It is harder for me to imagine the pain that Julie had and she could not get up to walk. It is really amazing to think about what human are capable of doing. Is there really a limit of our body? What do our coaches mean when they say “push strong?” I think we can push as hard as we can if there are actually no limits of the body. Our body works by cooperating different systems within it. According to the story of Julie Moss and Patrick, they reached their limit of what they can do. They did all they can and sort of approached the maximum capacity of their bodies. It is hard for me to imagine what my limit of the body would be. I think people can accomplish a lot before they reach the limit of the body. We would not know if we don't push strong or really work into it. The limits would not really exist or matter unless you try to explore it.

Oct. 10 2016 11:13 PM

I felt really depressed when I heard about Julie Moss’s story. It is harder for me to imagine the pain that Julie had and she could not get up to walk. It is really amazing to think about what human are capable of doing. Is there really a limit of our body? What do our coaches mean when they say “push strong?” I think we can push as hard as we can if there are actually no limits of the body. Our body works by cooperating different systems within it. According to the story of Julie Moss and Patrick, they reached their limit of what they can do. They did all they can and sort of approached the maximum capacity of their bodies. It is hard for me to imagine what my limit of the body would be. I think people can accomplish a lot before they reach the limit of the body. We would not know if we don't push strong or really work into it. The limits would not really exist or matter unless you try to explore it.

Oct. 10 2016 11:11 PM
Robert Thomas from Santa Clara

"Energy drink"? "Tasted the same"?

Contained calories? Didn't contain calories? Sucrose? No sucrose? Glucose? No glucose? Fructose? No fructose? Any other accharides? No other saccharides? Caffeine? No caffeine? Taurine? No taurine?

Value? No value. Meaning? No meaning.

Journalists: not scientists.

Feb. 27 2016 04:30 PM
Zihan Liu from Christchurchschool, VA

I am a sports person that always like to do some exercise to challenge myself. It is incredible how the iron man worked, and I kind of cannot understand the point Julie could not finish the last ten feet since she had done so much before, and there was only ten feet left. I do not believe anyone could finish RAAM even though there was people finished it. It was just insane and crazy how it went, sleeping one or two hours a day for ten days, and rest time just riding bike in all kinds of hardships. How illusions distracts bikers were also a fun part to listen to, I always think to push myself in a suicide run or conditioning practice, I do not have any illusion, but I do think a lot of other things to push myself to finish it strong. SO illusion in either truly helps people a lot.

Oct. 05 2015 02:00 AM
Frank from Christchurch

Mental Stress & Physical stress

From my perspective, it is an interesting episode. After listening all tree episodes, this one indicates the metal stress could change the situation of a human being. Undoubtedly, people could fall apart if the pressure on the physical part is too much. However, mental stress sounds more seriously from this podcast. For instance, the experiment of the energy drink is a great example illustrate that the energy drink is only working when athletes are acknowledging they are drinking and getting support from the drink. The group of athletes, who got shot to get the energy, does not have a good efforts then the athletes, who do not drink the energy drink but hold the drink in their mouth. Therefore, all of the efforts from energy drink is from the mental, not actually physical. Therefore, i think if people want to reach his of her physical limits, he or she needs to reach the metal limit first.

Oct. 05 2015 01:32 AM
Di Wei from Christchurchschool, Christchurch, VA

As a person who is not really a big fan of sports, I am really impressed by the concept mentioned in this podcast. All the astonishing ideas are now all stays around my mind.
In the radio lab, the interview for Julie Moss and Wendy Ingraham actually depicts or introduces the basic concept of the limitation for human when attending a marathon race. During the conversation, it says how those spectators described a exhausting human with all the energy used. According to what those observers said, she was so exhausted that she had nearly no energy to sustain for standing there or even walk for one step. It shows that when your body is under certain circumstances, your body will be unable to be controlled by yourself. I have my personal anecdote about playing video games all night without sleep and then playing another night of video games continuously. The feeling was so strange and nearly dead that I cannot control my body in some extent because I cannot really concentrate for real. Additionally, my legs are unable to support my body anymore. That was not a really enjoyable experience for sure when I think I already depleted all my energies, water and sugar in my body.
However, the truth is that these bad feelings might be warnings from my body's governor when my body still owns energy. The radio says something really attractive about how the body system will give you some suffer as admonition when you use lots of your energy but not all of them. It may calls your attention even there are still 1/4 energy left in your body. Therefore, even you feel really exhausted or nearly dying, it doesn't mean that you are really run out of sugar and energy for real. It may just the caution from your body system.
In another hand, the concept or lab about how those people get glucose from swigging the sports drinks instead of swallowing those drinks. It is such a interesting lab that catch my attention immediately. It is so inspiring that we can keep exploring how our body system is working.

Oct. 05 2015 12:44 AM
T Carrington from White Stone, Va

The Paradox of a super athletic world

The intensely motivating yet comparably frightening accounts by Julie Moss and the long distance bikers makes me wonder just how far humanity can go. Thinking solely in the physical dimensions of humanity, we have not gone very far. The average athlete has a base strength, can run, and is agile. Super athletes like Lebron James, Michael Jordan, and Adrian Peterson have proven over and over that they can push their bodies further than thought possible. Just thinking hypothetically, imagine if there was a way to get over the first step of becoming a super athlete and everyone began testing human physical limits. Human limits would be stretched further everyday. The overall gameplay of an NBA or NFL game would skyrocket. The games would be faster paced, athletes would jump higher, and the game would become more competitive than it already seemingly is. However, this theory is a paradox within itself. Many would think that if the overall limits of athletes were pushed far ahead, seemingly unbreakable records would be totally shattered. Rushing yards and points per game would be much higher. By looking further into this theory, you see that if every athlete is pushing their limits to the max. Some will still be more athletic than others of course, but the results of games would stay the same. Records would not necessarily be broken because the overall gameplay is improved, not just the individual. Adrian Peterson on a limitless level is still getting tackled by an also limitless Clay Matthews in the divisional championship. In other words, the game is just sped up and more powerful… nothing more.

Oct. 04 2015 11:35 PM
Iris from VA,, Christchurch

It is interesting to associate the the Calculus concept of limit with this real life experience.
After listening to the episode and connect it with my Theology class, I begin to think: Is there really a limit? Is it possible for human to unlimitedly extent the limit? If there is a limit, does it lay at the place that separates yes and no, life and death, true and wrong?
Another thought is about the limit of human spiritual power. am reading a book called "Men's Searching For Meaning." It is a memoir by a jewish psychologist about his experience in the concentration camp. In the concentration camps, despite the extreme dehumanization that was being imposed; a lot of Jewish prisoners remained their sense of value. They did not chose to die, nor did they chose to let the Nazis step on their deepest dignity. This power is immense, especially when they were in the situation of extreme lack of nutrition, intense work and humiliation.
Where does the limit exist?

Oct. 03 2015 08:47 PM
Matthew Schaefer from Christchurch VA

Our calculus class listens to this episode at the end of the first chapter on the mathematical operation limits. It is a nice way to tie in the abstract math concept, to what we intuitively know and experience with human behavior.

Sep. 25 2015 05:59 AM

When I first heard this story on podcast I was shocked to hear about Bob Breedlove that had died during the race and that I was friends with a daughter of his. Great story.

Oct. 21 2014 08:08 PM
Ronnie Falcao from Mountain View, CA

About the study where people on exercise machines were randomized to swig either a real energy drink or a "placebo" energy drink: fluid and glucose can be absorbed through the mucous membranes of the mouth. So the study subjects who were swigging an energy drink were really getting some fluid and glucose, even though they weren't swallowing it. I'm a midwife, and we use this with women in labor who are vomiting. They can hold juice or an energy drink in their mouth, and some fluid and glucose will be absorbed directly into the bloodstream through the mucous membranes.

Oct. 18 2014 04:23 PM

What is the xylophone song played on this podcast?!

Apr. 23 2013 09:54 AM
Colon cleanse Bloating gas

WOW just what I was searching for. Came here by searching for Radiolab

Mar. 06 2013 11:39 PM
Dona from Barcelona, Spain

I remember watching this Ironman as a pre-teen on TV with my mom. We were both horrified and screaming at the screen for someone to save that poor woman. Every time I see an Ironman event now, visions of Julie come to my head and I always wondered what happened to that unstoppable woman. It warms my heart to know that she's alive, well, funny and thriving.

Sep. 05 2012 06:19 AM
Jason Karp from San Diego, CA

As an exercise physiologist and running coach, I found this broadcast very interesting. I've always been fascinated by the science and limits of athletic performance, which is what drove me into this field.

Jason Karp, PhD

Sep. 03 2012 09:44 PM
Sandi from Turkey

Just a couple of days ago I had just listened to this podcast and used Julie Moss's story (and the video I found on YouTube) to encourage my daughter to continue in the 'race' she is running. She is going through a kind of mental marathon as she prepares for the university entrance exams here in Turkey. Thanks so much for this podcast!

Mar. 06 2012 02:41 PM

I was a few weeks away from my first Half Marathon. Despite months of training I didn't think I would be able to finish. I headed out on a training run with my ipod with newly downloaded RadioLab podcasts. As I ran that day I listened to the "Limits" podcast for the first time. That podcast was a turning point for me. It made me realize that running was as much about mental endurance as it was physical training. I've run several Half Marathons since then.
Thank you Radio Lab for this inspirational show.

Oct. 17 2011 07:53 PM
David from Melbourne, Australia

Great episode guys, very inspiring for endurance athletes. I was saddened to hear that Jure Robic was killed in a bicycle accident while training in Slovinia in September 2010, a great loss.

May. 26 2011 02:08 AM
J.C. Armbruster from Olympia, WA USA

I was caught up in the drama of Julie Moss' Ironman crawl to the finish. But I felt deprived of what Moss could have told us about how the event formed (or reformed) her life AFTER the competition. I felt the rest of the story was left out. Lack of time?

Apr. 08 2011 10:54 PM
Luke Ollett from Santiago Chile

3 meters to go

He pulls ahead with a lurch of his bike and suddenly the world is awash with failure and heartache. I travelled so far. I trained for so long. I worked so hard. And like a rabid bat, my hopes for redemption flutter away beyond my grasp. I consider taking him out in a spectacular climax to what would otherwise be a boring story.

1 meter to go

I often visualize what life would be like if we lived every minute of every day in the final passionate throws of a bike race sprint. Once you got over the fact that we would all be walking around with our tounges hanging out and wearing spandex, we would realize that our world suddenly became conquerable and was no longer a mystery. It is at this time that life finds new ways to exist. Like the infinitely split atom that will forever keep getting smaller, life can find new existence when pushed hard enough. Like the cold fusion power plant that I am, I chuck, hurl, roll, and muster even more energy and strength to frantically launch my body into an epileptic frenzy. I am moving so fast I appear to be a blur to the wall of onlookers I am about to eradicate. I look to my right and see myself. An exhausted vessel of emerging life, finally climaxing after many an hour of fore play


Standing on a podium, thats pretty cool. Having some fat guy drape a medal around your neck while you lift the flowers and shake your fists to the crowd in anger and love, oh that’s nice. But pushing yourself past a limit of pain that you thought never existed, and likely doesn’t exist anymore, is a gift and pleasure that can not be equalled by most anything on this planet. Bring on the pain.

I thought that sums it up for me ... from

Mar. 24 2011 07:59 PM
V from Des Moines IA

I was listening to the this podcast when I was working out...very interesting timing!! I'm wildly out of shape and my body was screaming at10 minutes on the treadmill for me to stop. I couldn't very well do that if I was listening about a woman who crawled to the finish line!!
I did wish i'd had some sport drink to swish though.

BTW-Radiolab is unbelievable, every time I listen to it I'm floored with what I learn.

Nov. 12 2010 05:53 PM
paul solon

when hallucinating one has to stop if he thinks his hallucinations are real. if not he can crash and can end his race.

by the way, juri died a few days ago, hit by a car, cause of accident unknown. it is terrible news.

paul solon, italy

Sep. 29 2010 05:37 AM
Lis Riba

The descriptions of the bicycle race sounded scarily familiar to June Havoc's descriptions of the dance marathons she participated in back in the 1930s. [Look up her autobiography, "Early Havoc" - a fascinating read]

May. 30 2010 11:28 PM
Andrew Cathcart from Australia

Fantastic podcast, great insights.
I finished my second, 24hr MTB race 2 months ago. I felt Julies pain when she was passed near the end.
The first time I did a 24hr I stopped to stretch for 2mins every lap (about 35min laps)Finished very fatigued and sore, but uninjured. My goal was just to finish, and I finished second :)
The second time (two months ago) was very different. It was a World Titles qualifier event, I wanted to push harder and it was a stronger field. I did the first 6hrs without stopping, had drinks and food passed to me on the go. Minimized my downtime when getting lights etc by swapping bikes. Average HR 8hrs in was over 150bpm, I was going too hard. 20hrs in was coming 3rd and feeling good, but struggling to eat and drink enough. With 2hrs to go I was passed, by one then later another. My last lap was insane, I struggled around walking half the way and crying out in pain each time i got back on the bike. Half way round the last lap we went past the transition and I had the opportunity to pull out by just walking 50 meters to my tent. I sobbed as I pushed on past choosing to suffer for another 4km. But I FINISHED and came 5th. That night the toxins in my blood from broken down muscle had me in a weird all over pain like nothing I had ever experienced. A week later I had surgery to remove large and deep areas of dead tissue from my buttocks on both sides. Long periods of sitting and pounding had cut off the circulation. Now 2 months later I'm back on the bike, for short and uncomfortable rides with my 7yr old son, who calls me "Dead arse Dad" ;) Going to be a slow recovery, not sure what the future holds for me. Part of me want to do endurance racing still, but maybe not 24hrs.
I hope my wife doesn't see me looking at the RAAM website :)

May. 17 2010 12:33 AM
Carin Abrahamsohn from New Jersey

This story reminded me of a great documentary called "Big River Man" -- he swims entire rivers, and this documents his way from the source to mouth of the Amazon. He experiences something very similar...

Apr. 30 2010 06:36 PM
Kenny Mac from 07003

I crewed for a RAAM womens team in the 90's and was awed hourly. They were in peak shape physically but it's impossible to train for the mental strength it takes to complete the race. We had one gal suffer from dehydration from a dance with in the AZ desert and go down for a day. The others pulled even harder awaiting her teammates return. The riders slept for 3 hour shifts, support slept when we could. We passed by the solo riders who appeared to be asleep on the fly

Apr. 30 2010 04:37 PM
Paul Bardis from Plattsburgh, NY

The 24 Hour Solo Mountain Bike Racers are another one to check out. The bikers at the last world championship raced over 200 miles and climbed a total of over 30,000 feet on rugged rooted, rocky, dusty, grizzly infested trails - stopping for only moments at a time and getting no sleep. They are in the same category as these other endurance racers. They all amaze me.

Apr. 23 2010 10:35 PM
Ted from Louisiana

To Skipper from Palo Alto, CA: The Texas Water Safari is another such event. It is a 260 mile canoe/kayak race with a 100 hour time limit. I completed it solo in 2006 which was a hot, low-water year. I look back on it now and wonder how in the world I did it. I was 57 then and it was my second attempt, having failed in my first attempt 2 years earlier. Even though one feels TOTALLY spent, the body still finds a way to continue and finish.

Apr. 20 2010 01:00 AM
Angela Meadon from Durban, South Africa


Apr. 19 2010 11:55 AM

I was wondering what happened to Julie Moss and the others after the event/race?
Physically, were they hospitalized, treated in some way? What did they do to recover and was there any long term effects? The memory people suffered in a different way not brought on by their ambition or drive.
Love the Lab

Apr. 18 2010 09:28 PM
Susie Mouri from Fairfax, VA

RAAM is Race Across America -- -- not Ride Across America. Two very different things.

Apr. 16 2010 11:07 AM
Marian from Louisiana

per Skipper's question, there is a similar ride across Africa. I remember reading one rider's blog. I did a search and found

Apr. 13 2010 12:10 AM
Sandi from Madison, WI

I was a little disappointed that the discussion on The Limits of Knowledge didn't include Thomas Kuhn's "The Structure of Scientific Revolutions".

That warm, fuzzy "Aha!" moment in the grand world of science is a (pardon me) paradigm shift. And sadly, those of us living in the old paradigm cannot even vaguely imagine the new paradigm until one creative mind can see it differently. (See examples: Galileo, Newton, Einstein)

Apr. 12 2010 06:33 PM
Matilda from New Jersey

I loved the whole episode (I've been a fan of the Ironman for a long time, too), but is that a gamelan I hear in this section?

Apr. 08 2010 11:04 AM

I was moved when I heard Julie's story, but I actually cried when I saw the clip.

There are certain things we hear or see that we consider life-changing. Seldom do we really change. Yet, I do think seeing Julie crawl to the finish line could be one of the most cathartic scenes we could witness witness.

Apr. 08 2010 08:55 AM
Skipper from Palo Alto, California

As an additional anecdote in this theme, I highly recommend Ken Kamler's TED talk on the terrible Mt. Everest disaster for which he was the primary doctor. Many people died, but one particular individual could very well have been featured in this Radiolab.

It's worth the time:

Apr. 07 2010 07:13 PM
Skipper from Palo Alto, California

@Andrew I think you've on the right track, but suicide is not a goal for the people in these stories. They are somehow able to transcend or bypass the human survival instinct, so it is similar to the way we can commit suicide of our own volition, but the 'death' here is only temporary; even accidental (e.g. hallucination).

Apr. 07 2010 04:27 PM
Andrew from Columbus, OH

Suicide can happen via bike, triathalon, or pain killer. Our limit is our ability to kill our self. Radiolab should have discussed this.

Apr. 07 2010 02:58 PM
Skipper from Palo Alto, California

Some amazing feats of endurance emerge in these events! The fact there are enough people to turn the Race Across America into a 10 day competition is mind-blowing by itself.

Does anyone know of similar events (perhaps a list somewhere?), or of other incidental case studies in physical outliers?

Apr. 06 2010 02:49 AM

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