How much exercise is too much? | Tim Noakes | TEDxCapeTown


Translator: Cathrine Ulstrand
Reviewer: Emma Gon So you see what I don’t understand is why I have to go through all this pain. But when I do see something I don’t agree with I become addicted to try to answer what is the truth. Today I’m going to talk about some of the ideas that I’ve focused on. They come in many different topics and you can see they cover medical problems in marathon runners. Rugby injuries. Are all rugby players overplayed? Something about nutrition. Should we be eating carbohydrates or should we be eating fats? And particularly what regulates
our exercise performance? And then, is it possible to swim at the North Pole at -1.8°C in a speedo? So I’m going to talk about those questions and I’m going to begin by the very first question that ever came to me as a scientist was: Are marathon runners immune to heart disease? And this was a theory developed by a Californian pathologist and he said on the basis on any contrary evidence, it looked like if you ran a marathon you’d never have a heart attack. So I mean I knew that it was absolutely bogus but to prove it was all the more difficult. At the time in the 1970s this was the bible of running. It was written by James Fixx and he described at length the whole hypothesis. Tragically seven years after this picture was taken James Fixx died of a heart attack while running. But by then we had in fact already shown that it was possible for people to have heart disease. So we looked for when we saw reports of people dying in marathon races we would go and collect their hearts and we would examine them and eventually we found the evidence and so we published a paper in the New England Journal of Medicine showing that there were runners who had disease and the disease here is — this is coronary artery disease in which there’s obstruction of the coronary arteries causing heart attacks and we were able to show that this man had had a heart attack whilst he was running a marathon. So that was published and so that disproved that’s obviously very easy to do,
it’s easy to find a few cases that disprove a theory. The next one that I really got involved with is in the 1980s was: Should we be drinking more or less during exercise? And at the time in the 1960s it was held that actually if you drank during exercise that wasn’t a very good idea. Abebe Bikila who was the first African runner to win two Olympic gold medals in the 1960 and 1964 Olympic marathons he ran both races without drinking anything. That was what runners did in those days. And then all of a sudden in the 1960s and 1970s things changed and we were told that if you didn’t drink enough,
you were going to die during exercise. I became interested in why that would be the case. And the epiphanous moment
occurred on 1 June 1981 when an athlete started
the Comrades Marathon in Bourbon and she reached 70 km and her husband withdrew her from the race because she didn’t recognise him and he felt that wasn’t a good idea. (Laughter) And he then took her for medical care and in short order within two hours she was unconscious having epileptic seizures, and she had to be taken back
to hospital in Bourbon. And when she was admitted to hospital she became the first case of this condition which — a long name we don’t need to understand what it is at the moment. But here’s her chest x-ray and this shows that she’s got fluid in her lungs and it took five days later before the fluid had gone out of her lungs but this is what happened what really happened was that her blood sodium concentration which should normally be at 140 and is tightly regulated, it’s one of the most regulated features of the body had dropped to 114 that’s heroically wrong, something had gone tragically wrong and she asked me what had happened and I said, “We have absolutely no idea.” and it was the first case in the world so we had no idea. Over the next four or five years we picked up couple of more cases and worked out that they probably had overdrunk and in other words they’d drunk too much during exercise. And then at the 1988 Comrades Marathon we could prove it by hospitalising eight people who were really sick with this condition and follow them during their recovery and we were able to show that they all passed an excess of fluid during recovery and so this athlete here passed six litres of fluid extra during recovery and that she had dropped
her blood sodium concentration to a very low level and you can see there was a nice relationship. So the more you overdrink the lower your sodium and the sicker you were and we published that in 1991 and thought that’s the end of the problem. We cured the problem, we know what causes it, it’s overdrinking and we thought the problem would go away. But unfortunately at the same time
we were doing that, industry would come along and said, “No actually, the more you drink, the better.” So there’s an advert saying that not only must you drink but you must drink heroically during exercise this is 1.2 litres per hour or your performance will suffer. And we predicted what would happen, we predicted this would happen. And this is the incidence of this condition accumalative incidence of this condition which had never existed before 1981, never existed There were a total of 1600 cases in the medical literature this is not all cases because many were not recognised and tragically twelve deaths, all completely avoidable. And so what happened was that the sports drink industry came along then and then they influenced the official drinking guidelines drawn up by official bodies and those promoted overdrinking. Then a lady died in the Boston Marathon in 2002 and in 2003, I was invited by two organizations to produce alternate drinking guidelines which promoted drinking to thirst and that finally has now been accepted that that is the way we should be drinking. But you can see what the cost of that disease that had never existed came along. And finally the book written about the whole sorry thirty-year saga was released recently. And what I was able to show was that the science of hydration is utterly bogus. There is no science to it, it was dreamed up by marketers to sell a product and I’ll come back to that point in due course. The next question that really has intrigued me was: Do muscles regulate exercise performance or is it something else? And it’s really interesting in sport that you see such close finishes. And this was the 2000 ten thousand
meters in the year 2000 and you can see that Haile Gebrselassie
has won this race by a few inches and it’s a race that goes on for twenty-five minutes, so how can a twenty-five-minute race come down to a few centimeters? And the argument is that the reason why the athlete comes second is because his muscles offers too much lactic acid and that causes him trouble so the athlete who comes second, his heart is unable to pump
enough blood to his muscles so they become anaerobic and as a consequence they produce lactic acid which you all learned in biology causes muscle poisoning and stiffness and everything that goes wrong in sport is a related to this terrible product lactic acid. Over time, it took us a few years but we realised this model can’t be right it can’t be true for a very simple reason. That it’s brainless. Fatigue in this model is caused exclusively by the failing muscles. So the brain can’t influence your performance. So what you think is utterly completely irrelevant. All of you know that’s rubbish because motivation must have a role in some way in sporting performance. So we did a lot of research and then finally we realised what the evidence was. Again it just takes one insight to see these things. This is Haille Gebrsellasie running 10 000 meters. This is his average pace for each kilometer and what do you notice? He runs the fastest the last kilometer. But how can that be? How can he run his fastest when he’s most fatigued? And all that tells you is that fatigue as we describe it has got nothing to do with
the physical side of your body because he’s performed much better when his muscles are the most tired. So therefore we worked out
that fatigue is purely an emotion it’s what your brain is making up it’s completely fallacious emotional information that your brain uses to make sure that you don’t die
during exercise. (Laughter) And so we eventually came up with this model the Central Governor Model of Exercise which originally was critizised when we proposed it in 1996. People said, “You’re mad!
How can it possibly be true?” I’m glad to say that there are
multiple Olympic athletes at this very moment training
according to this model and acknowledging it that they are now training because they understand performance. And what this model says simply is that the brain regulates your muscle performance and that feeds back to your brain and then there are other factors like motivational factors and I see my time is running so I’ll have to go a bit quickly. That there are a whole bunch of factors that influence your brain and then you start exercise
at a particular work rate which is different depending on
how far the activity is. You always have reserves you always finish with, you could always exercise harder. There’s always an end spurt and finally, there’s always feedback to the brain. So that’s the way the system works. And as I’ve indicated it’s now becoming accepted. The next question: Is it possible to swim 1 km at -1.8°C in only a speedo? The person who asked me
that question was Lewis Pugh. We, just approximately five years ago travelled to the North Pole to swim have him swim 1 km and I had to make sure he returned alive. It all began when he said, “Can I swim around the Cape Peninsula?” and I said, “Yes” and everyone else had said,
“No. That’s impossible.” So he went out and swam around the peninsula. It took him thirteen days but he managed to do it. And when he finished he said “Can I now go and swim at the North Pole or in the Arctic where the temperature is 0 to 5°C?” and I said, “I can’t guarantee that you’ll live.” However, fortunately, there’s a picture of him diving in we were able to have him swim succesfully in the Arctic and in the Antarctic. And what we’re measuring here
is his temperature response as he swims. And you’ll see that his temperature drops very little during the swims and it drops mainly afterwards and this was a swim of 1 mile and you can see his body temperature drops quite dramatically near the finish and he was absolutely at the limit of his abilities. This is his muscle temperature which is much lower notice this is 32°C and even an hour an a half
after getting out of the water his muscle temperature was still 32°C so he was just a warmed-up body centrally but his legs were still absolutely cold giving you an idea of how tough that was. Here he’s swimming essentially five years ago at the North Pole a picture of the South African flag. Now, the final topic is the one
that’s going to keep me going for the next twenty years is: Are low-fat diets healthy for you?
(Laughter) (Applause) And where did it come from: in 1977, the American Senate decides that we must change our diets and we must cut out all the fat and we must put lots of carbohydrate in and that report was written by a vegan who had no training in nutritional sciences. (Laughter) So this is what happened
to your beautiful breakfast and I must just tell you that those eggs are one of the most nutritious foods
that you could possibly eat. And what’s the evidence against it — there’s lots. But let me tell you the French who do very well in terms of their hearts they do everything wrong as far as their diets they eat much more saturated fat but we now realise that there are populations that eat much less fat in their diet and have much more heart disease than these populations down here which eat a lot of fat and
have very little heart disease. So the concept that heart fat
causes heart disease is completely bogus. And finally it’s been realized — there’s a paper, a meta analysis
and that’s an analysis of all the studies that have ever been done and what it shows is this that there’s no evidence that your dietary fat is associated with heart disease whatsoever. So if you’re scared of eating fat you may now stop get rid of that scare here’s the evidence for that case So what happened unfortunately as we went through this was that it took us millions of years to get to that and 27 years to get to that. And this is directly related to the increased carbohydrate and processed foods we’re eating in our diets. So finally, my summary Challenging Beliefs what I’ve learned in life is that 50% of what we teach is wrong the problem is we don’t which 50% it is. (Laughter) (Applause) Our job as educated people
is to spend our lifetime trying to figure our which 50% is which. Until it is disproven accept that for which the evidence
appears solid and logical and is free of covert or overt conflicts of interest because unfortunately, industry
is driving what you believe in many many things. But don’t ever dismiss lightly that that for which there’s credible evidence that’s reverse gullibility there’s such clear evidence that the diets we’re eating today are horrendous and we need to change them and we shouldn’t be ignorant of that. Question everything else but eventually the truth has to prevail. It always prevails. So aim to be on the side of the truth. Thank you very much for your attention. (Applause)

100 thoughts on “How much exercise is too much? | Tim Noakes | TEDxCapeTown

  1. This contradicts much of what I have learned about the success of a whole food plant-based diet. This talk is a waste of time.

  2. Obviously the graph of CUMULATIVE number of cases of EAH and EAHE ramps up over time! But showing that graph with the addition of the comments is deliberately DECEPTIVE. What motivates this deliberate deception? Was this a covert test of our critical scientific faculty?

  3. So let’s just go against everything that’s already been proven to be true. Also fatigue is just an emotion?!? Try running a 100miler those guys are destroyed at the end. Look at Dean Karnazes

  4. The point science is missing is stress on the body, period. Any stress causes heart problems. If you eat eggs from sick gmo farmed birds or cows eating grains and pumped with antibiotics, it's a different food and probably as much stress on the body as vegans eating processed food all day. Running too much is stressful on the immune system. People with lowered immune function get sick when exercising for this reason. That guy swimming in artic waters probably has an amazing immune system. I imagine his family generations missed out on mercury tinctures or drinking from lead pipes or something.

  5. Your brain is telling you something for a reason. What do you think will happen if you ignore the signals your brain is trying to tell you.too many scientists in their world wasting our resources

  6. he seems to completely miss the fact that distance runners run races tactically and are often consciously reserving their energy for the end of the race. you dont try and run your fastest at a constant pace.

  7. What a disappointment. Also leave nutrition to people who knows about it: Neal Barnard, John McDougall, and the likes!

  8. Well, I came here to learn about how much exercise is too much. I'm a little peeved that the talk had nothing to do with that question but I did learn some new things so I'm not entirely mad.

  9. He says overdrinking is bad, but drinking what? water or isotonic drink? If drinking too much water makes sodium concentration go down, are sotonic drinks good or not? and how much do we have to drink, 1 liter per hour? So many unanswered questions, the first one how much exercise is too much

  10. Just when I thought I'd get to a point or find answer, it just flew all around in a flurry! Had to come to the comment section to maybe get the answer to some degree.

  11. The talk wasn't really related to the title but it was fantastic and essential! Excellent lecture just they need to edit the title.

  12. Iker Casillas….the goalie of the Spanish National Soccer Team and currently working as goalie for a Portuguese 1st division team (Porto FC) just had a heart attack…..

  13. Why this talks are not done for the greater amount of people?….right now they get so technical…..

  14. I ran a marathon about 10 years ago and weighed myself before I left the house for the race at 185 pounds. I drank at every water stop possible and drank a LOT of fluid after the race then weighed myself when I got home and I was 178 pounds. This was all water weight that I put back on over the next few days, but it shows just how much water you can lose via extertion and the importance of replenishing not only your water but your electrolytes.

  15. So, "How much exercise is too much?" —– did he ever answer the question directly?? he showed marathoners' hearts and other things, including the truth about diet… but can we know WHEN we got too much exercise??

  16. Basically eat the Keto diet, or carnivore diet, and don't become a marathoner for a living?? 

    Stands to empirical reason that anything extreme in any exercise will have health consequences if done repeatedly. And who doesn't do that after you taste victory!!

  17. This MD is promoting unhealthy meat & dairy consumption. He may not know which 50% of what he teaches is wrong but nutrition doctors do. Eggs & meat cause heart disease, diabetes, and 85% of cancers. He's a shill for the meat & dairy industries.

  18. if only tim noakes was interested in facts and rigour,he might not have made south africans a laughing stock in the world of nutrition science.

  19. Keep moving and drink when you are thirsty. Don't drink or eat too fast. Fatigue is an emotion and affects you motivation. Fatigue responds to pain which is also linked to the emotional part of the brain. Mix of fats and balance diet(Protein, Fats, Carbs) is better. Watch out for carbs and sugars.

  20. This Prof has got himself type 2 diabetes. If an expert can't take care of his own health, he is no expert.

  21. Dudes sloppy and lazy. It's clear he hates exercise! Who's to see he doesn't have any obstructions going on in his lousy physique!

  22. Wow. I’ve ran 12 marathons, and I can tell you the reason that guy can run so fast in the last bit of the race, is because he was conserving his energy. Any semi-professional runner would know that. He’s not running as fast as he can throughout the entire race, and he’s concerning his energy for the last kilometer. He’s not at his most tired before the last kilometre like this guy says. That’s against every standard and technique I’ve ever studied in running.They made an entirely hypothetical Model without even consulting the runner from what it sounds like. I don’t necessarily dispute their conclusions per se. How they got there was completely through a guessing game. One that does not hold truth to us marathon runners techniques.

  23. This is what happens when the person conducting the study doesn't even participate in the subject. Like getting a tattoo from someone without tattoos

  24. Regarding muscle fatigue, he is generalizing way too much. You can, in fact, beat fatigue mentally, but there IS a limitation to that. It’s really hard to hurt yourself by pushing past fatigue if you were in proper shape and well rested before the event, but if you were not either well rested or in proper shape, you could injure yourself. Your muscles literally start to tear when you push the limits and if you don’t get in proper shape and rest enough, you will pull a muscle. What he was talking about was probably the balance of stretching and relaxation in running technique. Many runners (even elite) do not get completely stretched and relaxed until well into a race, especially the longer races, like a 10K. And his explanation of the slide showing the speed of the 10K runner throughout a race was complete bogus. The speed pattern there is based on competition, not perceived ability. If he put up a slide that showed a record attempt, the speed pattern would be nearly a straight line, not quite top speed, because it’s such a long race.

  25. Don't agree with the conclusion, it is not that fatigue is purely emotion, the runners obviously conserve energy, if you blow it all in the first 100m you are going to lose.

  26. Some very interesting concepts . Some of which i have pondered about previously and not known any better besides using personal observations . I have found siping on water when thirsty and that to just to get maybe a gulp down but thats it hydration during exercise is a little different than drinking like you would through your normal day to day activities.

  27. 10:00 that may be true in cardio activities that rely on O2 for energy, but not in strength activities like sprints or weightlifting. Once you’re done, you’re done. There is no reserve. No more ATP, and the muscle has been stressed with no energy source left.

  28. The Title has to change but still you have very informative and scientific evidence to show that the sports drink industry has been deceiving the American public for too long and that it must be changed in order to cut the number of deaths due to overdrinking. Thanks.

  29. After listening to that video I realized that Tim Noakes is a snake in the grass! He did answer the question on “how much exercise is too much” through covering so many interesting topics. The answer comes very clear. Nobody in this world can answer that question. If you ever meet somebody that claims that he can put an answer other then there is no limits or it depends on so many facteurs just run away as far as you can from that person. Very refreshing to hear somebody who laugh at the biggest oaks of the century which made so many people obese. Brains like Tim should tackle the current problems of immigration that we are currently having to determine what is the best way to handle the situation.

  30. He basically said that you decide how many exercise is too much for you, because fatigue is an emotion, examples of running and swimming were to show this.

  31. This talk is a logical paradox. If by his own admission 50% of what is taught is rubbish, then the question I am asking is: what 50% of this talk is BS? Clue: the injunction on fatigue.

  32. This guy does not do weight training. What the heck does he know about too much or too little exercise. Running is just one faction and weight training is way more important.

  33. The problem of many of these scientists is most of them can’t articulate their messages properly and keep hopping from one thing to another and getting further from what they initially want to talk about, and in the end, no one gets his message, he is just throwing meaningless stats one after another without having an actual context relatable to the audience.

  34. This guy is us a doctrine about health and fitness and you don't appreciate it.
    Or maybe are not very bright to get it.
    Use your logic, you can exercise as long as you like: if you are old don't exercise for 2 hours like a young athlete, because your old bones will break. If you are eating ealthy and resting enough, don't be leazy tell your brain to get together and endure a moderate amunt of exercise. If you don't know how to eat healthy and how long or how intense, talk to your doctor about it. Use your common sense.

  35. Very interesting. Supports the fact that many of the studies we see and guides we read are not correctly vetted – too many unsupported “trends”.

  36. Until you can't recover from one exercise session enough to be stronger/faster/fitter etc (strength and fitness returns diminish on the exercise investment the longer you've been exercising for [in terms of years]) in your next exercise session is the answer to the title question by the way. If you're exercising to get better at it then then the must know rule is that (technically) the "exercising" doesn't make you better; it's the recovery (rest) from the exercising that make you better because this is where adaptation to the exercise stimulus takes place. So you can exercise too much to never recover enough for adaptation to take place. This of course differs from person to person and depends on a number of factors such as diet, sleeping habits, PED usage, genetics and the use of recovery therapy to name a few.

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