Thirst Signals and Individual Differences

When you're running hard, pushing yourself to extremes, which do you think is the more limiting factor, your body or your brain? Alex Hutchinson has done extensive research on exactly that question.

The Toronto-based author and journalist focuses on the science of endurance and fitness. You may know him from his book ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance or from Outside magazine where he's a contributing editor and writes the Sweat Science column.

Alex believes that our limits are elastic, stretchable, and as of yet, undefined. He and Coach Claire discuss those limits, and also tackle hydration, fueling, carbohydrates, strength training, aging and more. And just for fun, they also get into the science of why Coach Claire loves an out-and-back course way more than a loop!

Alex also writes the Jockology column for The Globe and Mail, and his writing has appeared in Canadian Running magazine, Popular Mechanics (where he earned a National Magazine Award for his energy reporting), the New York Times, and he was a Runner's World columnist from 2012 to 2017.

Prior to ENDURE, Alex wrote a practical guide to the science of fitness called Which Comes First, Cardio or Weights? Fitness Myths, Training Truths, and Other Surprising Discoveries from the Science of Exercise, which was published in 2011. He is also the author of the 2009 book, Big Ideas: 100 Modern Inventions That Have Transformed Our World.

Alex started out as a physicist, with a Ph.D. from the University of Cambridge, followed by a few years as a postdoctoral researcher with the U.S. National Security Agency, working on quantum computing and nanomechanics. During that time, he competed as a middle- and long-distance runner for the Canadian national team, mostly as a miler but also dabbling in cross-country and even a bit of mountain running. He still runs most days, enjoys the rigors of hard training, and occasionally races, but hates to think of how he'd do on an undergraduate physics exam!

Alex's best-selling book Endure has a forward written by Malcolm Gladwell, another famous Canadian runner and writer, and the updated version is now out in paperback.

Questions Alex is asked:

3:34 You are an author and a journalist, but you really seem like a scientist at heart. How did you get into writing about fitness and endurance sports?

5:22 What fascinates you most about how the body works when exercising?

6:10 Your book Endure, if you could really sum it up, I would say that it is trying to discover whether it's the body or the brain that's mostly the limiting factor when you're trying to go to extremes but it's clear that it's a mix of the two. You can't say, "Oh, it's just the brain" or "It's just the body." Can you talk a little bit more about how they're interrelated and what we are finding out?

7:41 Tim Noakes is a South African scientist that has been very controversial. He's written a lot of things that turned out to be totally true and then he's written a bunch of things that maybe people have not found to be true. Can you talk a little bit about the controversy, both the good and bad things that Tim Noakes has contributed?

10:35 I would love to distill the lessons that you've learned so far about things that can help runners do better. The two main topics I would love to get into are hydration and fueling. Let's talk about hydration specifically for the marathon. Hydration needs are different for every type of body. Are there any rules of thumb that recreational runners should think about when coming up with a hydration plan for the marathon?

15:25 'Drink to thirst' is starting to become more popular but there are some populations that their thirst isn't reliable. I've heard that as you age, your sense of thirst is not as strong. Have you heard that as well?

18:05 We could talk about fueling during the race or we could talk about nutrition in general, but what I have found is that human studies are just notoriously bad when it comes to nutrition because we're not rats and we can't put humans in cages and measure everything. So what would you say are the limitations to studying nutrition on humans?

23:53 Let's get into the great carbohydrate debate. As I often tell people, what's frustrating about the word carbohydrate is that lentils, lollipops, and lumber are all carbohydrate. And if you say do eat carbohydrates or don't eat carbohydrates, clearly those three things are processed differently in your body. First of all, why do we lump carbohydrate? It's an absolutely massive category of food and clearly our body treats it differently. Carbohydrate is the preferred fuel of the brain. It's the preferred fuel of the muscles. So why isn't everybody on the carbohydrate train?

25:35 Sugar or simple carbohydrate is bad if you're not exercising but it's exactly what you need if you are trying to run a fast marathon.

27:29 A keto diet could be exactly what an ultramarathoner would want to do. They're not so concerned about ultimate speed; they're concerned about eating all the time. Isn't that what they say about ultras is that it's not really a running race; it's an eating race?

28:58 What's the point of all this science if the answer is always "It depends?"

30:22 Let's talk about strength training. What is the minimum effective dose for a runner who is highly active and competitive but not at the elite level?

34:36 What is the minimum effective dose of strength training for somebody who is actively training to be competitive in a race but still at a sub-elite level?

40:10 I think a lot of what we attribute to normal aging is actually more of lack of activity, and all the decline is mostly for the couch potatoes, the more sedentary people, and we runners think that maybe we're immune to all of that stuff. Would you agree a little bit with that?

44:12 You recently wrote an interesting article about the science of finish lines or teleoanticipation and you related it to not knowing when the pandemic will end. Can you explain?

47:46 I like out and backs better than loops because I know what to expect on the way back. There's science that proves it, right?

49:28 The brain loves knowing what to expect and it predicts what's going to happen whether it's right or wrong, right?

49:42 What questions are left unanswered? What kind of science are you looking forward to in the future?

51:33 I think everybody wants to figure out how to make their brains stronger, not just in running but in life and dealing with little kids.

Questions I ask everyone:

52:22 If you could go back and talk to yourself when you started running, what advice would you give?

53:32 What is the greatest gift running has given you?

53:58 Where can listeners connect with you?

Quotes by Alex:

"For every situation that you think of the answer is both. The answer is "Yes." It's just like nature and nurture. The answer is your fate is 100% nature and it's 100% nurture, and your physical performance is 100% your body and 100% your brain."

"If you look at the list right now of the top 100 men's marathon times ever run, 98 of them have been run by Kenyan or Ethiopian marathoners so if they're doing something wrong, I want to do it wrong like they're doing it because they're pretty successful. And if you look at the data, in both cases they're getting more than 60% of their calories throughout the day from carbohydrates. And for the Kenyans, apparently it's more than 20% of their calories come from the added sugar that they put in their oatmeal and their tea. So is this healthy for a couch dwelling office worker in North America? Probably not. But if you want to run fast or if you're training hard, sugar is not only like you can use it, but like you said, you need it."

"There is some pretty interesting evidence showing that older runners like Masters runners get a much larger and more immediate benefit from weight training for their running than younger runners do because the younger runners have more muscle to spare."

"Your body knows, even parts of your body that you wouldn't think know exactly where the finish line is."

Take a Listen on Your Next Run

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Mentioned in this podcast:

Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance

Alex Hutchinson | Outside Online

Runners Connect Winner's Circle Facebook Community

RunnersConnect Facebook page

RunnersConnect Focus Classes

email Coach Claire

Follow Alex on:

Twitter

Facebook

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