Science Of Ultra | Ultra Marathon And Trail Running Expertise | World Leading Endurance Science And Coaching

Ultra marathon running physiology brought to you by the world’s leading scientists, coaches, and athletes. Science Of Ultra host, Dr. Shawn Bearden, brings you interviews and more to deliver everything you want to know about all facets of training, nutrition, hydration, environment, psychology, gear, and much more. Become your ultra best!
RSS Feed Subscribe in Apple Podcasts
Science Of Ultra | Ultra Marathon And Trail Running Expertise | World Leading Endurance Science And Coaching



All Episodes
Now displaying: December, 2015
Dec 29, 2015

My guest today is Jennifer Pharr Davis. She is an author, speaker, and a National Geographic Adventurer of the Year.

Jennifer is among the most well known of American long distance hikers. She holds the record for the women’s FKT for a thru-hike of the Appalachian trail; a record which was the overall outright record for several years and fell by only 3 hrs 12 minutes in the summer of 2015. She has hiked over 12,000 miles on six different continents, including thru-hikes on the Pacific Crest Trail, the Appalachian Trail (three times), the Colorado Trail, the Long Trail in Vermont, the Bibbulmun Track in Australia, and numerous trails in Europe and South America, including the Tour du Mont Blanc, which ultra marathon runners will be familiar with.

Connect with Jennifer:
1) On the trail!
2) Facebook: Jennifer Pharr Davis
3) Twitter and Instagram: JenPharrDavis
4) Her company:
5) Books: Becoming Odyssa and Called Again: A Story of Love and Triumph

She answered many questions on this in depth interview, including:

You hiked that AT in 2005, 2008, and the overall record setting year 2011. Your first women’s record of the trail in 2008 was a bit over 57 days; in 2011 you destroyed that record and did the trail in a bit over 46 days. How did that enormous improvement come about?

Would you describe the demands of a long-distance thru-hike? Granted that weather can have a big impact, what does a ‘typical’ day look like for a long distance thru hiker?

Are you ever running/jogging during a thru-hike or is it all hiking?

Tell us about your training for a thru-hike. In your experience, would a 3-4+ week thru-hike be good training for ultra marathons of 100 miles or longer?

How do you handle sleep deprivation, or functioning on little sleep, for weeks on end? Tell us about your nutrition for a thru-hike.

Tell us about your foot care on a thru-hike.

You wrote an article recently for the New York Times for which you explored the topic of sex differences, or lack thereof, in ultra distance events. Tell us about that.

Tell us about the psychological demands of a major thru-hike.

As an exceptional, experienced, and accomplished ultra-endurance athlete, you have surely had some very dark moments (mentally).
Would you take us to back to your darkest experience, tell us that story and how you handled it?

We wrapped up with some advice for ultra marathon runners interested in tackling a thru-hike.

Dec 22, 2015
My guest today is Patrick Wilson, PhD and RD. He is Assistant Professor of exercise science in the Human Movement Sciences Department at Old Dominion University, in Norfolk, VA, where he also directs the Human Performance Laboratory. He earned a Ph.D. in Kinesiology from the University of Minnesota, where he also received training in the areas of public health and epidemiology. He completed his post-doctoral research training at the Nebraska Athletic Performance Laboratory, specializing in sport nutrition applications for collegiate athletes. And, he is also credentialed as a registered dietitian. 
He has authored numerous peer-reviewed publications covering a wide variety of sport nutrition-related topics. He has conducted both laboratory- and field-based research examining the effects of nutrition on endurance exercise performance, including the effects of carbohydrate composition on gastrointestinal distress and performance during prolonged running. His studies have included marathon runners, ultra-endurance runners, and Ironman competitors.
In this episode, we cover all the angles on gastrointestinal (GI) distress as it applies to ultra runners. You learn the major factors that influence GI distress and how to maximize your chances of keeping your GI tract happy.
In the wrap-up, he answers two key questions.
1. What is the biggest mistake athletes make regarding food/drink intake and GI distress?
2. What take-home recommendation would you give for athletes to reduce their chances of developing GI distress in ultra events?
Dec 15, 2015

William is a 62 year old British and Scottish international athlete and has set 160 ultra distance running records (from 30 miles on the track to 3100 miles/ 5000 kms on the road) at World, British and Scottish level including age-group records.

Connect with William:;  Twitter: @williamsichel;  Facebook:

Since 1994 William has competed in 92 ultra marathons at home and abroad – winning 16 of them. He has also represented Great Britain 11 times and Scotland 7 times.

William has three grandchildren and has been self-employed all his life.

Since 1982 William has lived in the remote Orkney Islands, off the north coast of Scotland, 750 miles north of London.

In this episode we learn all about the training William follows to compete and succeed in extreme ultra endurance events.

Dec 8, 2015
My guest today is…you…and…me.
This episode is all about an amazing new project I’ve created for you. If you don’t want to hear about a new project I have for you, and only what the science on Science Of Ultra - then I’ll be back next week with another amazing Science Of Ultra episode. But, if you want more from me...
Have you ever wondered what it’s really like to have a coach for your ultra training? Is a coach worth the cost? Maybe you have a coach and you wonder how another coach is different. Will a coach really help you to become your best? What are the conversations with a coach like? How exactly does the relationship with a coach work? What sorts of workouts are prescribed? How will I feel following someone else’s prescribed plan every day? How flexible is a coach when life events happen? 
Wouldn’t it be great if you could have the ultimate observer’s experience…to listen to every word between a motivated athlete and a highly qualified coach…to have access to every detail of every workout (even nutrition)…to follow the athletes daily experience…to even be able to ask the athlete questions…the ultimate observer’s experience as if you were there with the athlete for every single step - a completely open book? Wouldn’t that be amazing? Would you like 100% access to follow the journey with an ultra athlete and coach?
That’s exactly what I’m bringing to you now. I’m calling it the Journey to 100. I’ve hired a coach and I’m going to make every aspect of my journey completely open to you, and you can ask me all the questions you like. For the next year, my coach is going to push me towards my first 100 mile race.
This opportunity for you is unprecedented. Never before has there been a completely open, 100% access experience to an ultra athlete’s journey to taking on their first 100 mile race. Nothing like this, with such total access, has ever been done and I’m bringing it to you.
I started Science Of Ultra with a single-minded focus - to connect you with the reliable, valid, and actionable evidence-based knowledge you need to make the most informed choices about your ultra pursuits. I hope that Science Of Ultra is proving to be valuable to you. I absolutely love bringing it to you.
I am now starting a second podcast. The Journey to 100 podcast will be published weekly, just like Science Of Ultra.
However, the Journey to 100 will be focused on giving you what we might call the ‘fly on the wall’ experience. You will be able to listen to my weekly recorded conversations with my coach, you’ll be able to read every workout on the web site, you’ll be able to investigate my nutrition, and you will get my blog posts about my personal experience. In addition, you will be able to ask me questions that I will answer in every podcast episode of Journey to 100. Science Of Ultra will always be exactly what it has been and we have more great science coming in next week’s episode. But, I am using this one episode of Science Of Ultra to let you know about the Journey to 100 because I want you, the loyal Ultra Clan, to be the first to hear about this exciting venture. 
So, how will this work. Well, keep listening to Science Of Ultra episodes every week...
Then join the Journey to 100. While you are on the web site, look at the navigation choices in the top menu. You will find a link to Journey to 100. Click on that menu item link. On the Journey to 100 page, you’ll find all the information you need to join the journey.
Have you ever wondered what the coaching experience is like? Are you interested in what it takes to step up to the 100 mile distance? Maybe you want to become a better 100 mile runner? Maybe you’re just curious. The Journey to 100 is for you! Go to and select Journey to 100 in the menu or go directly to it at
Although Journey to 100 will have it’s own podcast, separate from the Science Of Ultra podcast, I will use the same Twitter, Instagram, and Facebook pages to post for both. So, if you are already following, great! If not, go to and click on the respective follow icons at the top of the page.
When will you ever get to be completely on the inside of a coaching journey focused on a 100 mile ultra race? This is your chance to experience every aspect. Go to (or use the menu link at the top of the main page) to join your Journey to 100.
Dec 1, 2015
Science of Ultra   Episode 13   Carbohydrates for ultra marathon training and racing
My guest today is Asker Jeukendrup, PhD. He is a leading sports nutritionist and exercise physiologist who spent most of his career at the University of Birmingham (UK), where he was a Professor of Exercise Metabolism and Director of Research. He worked the last 4 years for PepsiCo as Global Senior Director of the Gatorade Sports Science Institute Based in Barrington IL (US). He is currently running a consulting business “Mysportscience” and is a visiting professor at Loughborough University. During his career he authored over 200 research papers and book chapters, many of which have helped to change the sports nutrition landscape. He is also the author of 8 books. He is the former editor of the European Journal of Sport Science and Associate editor of the Journal of Sports Sciences. During his career he worked with many elite athletes and teams including several World and Olympic champions. He also practices what he preaches and is competing in Ironman distance triathlons as well as other endurance events. To date he has completed 21 Ironman races including 6 times at the Ironman world Championship in Hawaii. 
You can connect with Dr. Jeukendrup:
Twitter @jeukendrup
Here are some of the questions Dr. Jeukendrup answers:
  1. On a daily basis, what are the carbohydrate needs of an ultra endurance athlete?
  2. How many calories can most people digest and absorb per hour when running?
  3. What is the fate of consumed carbohydrate relative to stores while exercising?
  4. What are the key factors to be considered with respect to the carbohydrates during a long event that may last 24 hrs?
  5. Can we predict when relative glycogen depletion might occur in an ultra marathon?
  6. What should we consider when we are choosing specific high-carbohydrate foods?
  7. What are the key issues to consider relative to the timing of carbohydrate intake prior to, during, and following training workouts?
  8. What about timing of carbohydrate consumption for a race event?
  9. Is glycemic index of a given food different when running vs at rest?
  10. For those who don’t like sweet tastes while exercising or late in races, what are the sources of simple carbs that don’t taste sweet?
  11. Are there data, or any good reason to expect, that any aspect of carbohydrate digestion/optimal sources/etc. will change over the course of an ultra marathon? Does carbohydrate physiology change when we go way beyond the better understood distance of marathon? 
  12. Is consumption of foods that contain protein, fat, or fiber a concern in light of effects on gastric emptying?
  13. When we consume carbohydrate during a run but prior to reaching very low levels of glycogen in muscle and liver, are those calories used more/less/equally to stored muscle glycogen?
  14. Can carbohydrate consumption keep us from reaching a muscle and/or liver glycogen depleted state?
  15. What is the relation between carbohydrates (type, source, complexity?) and likelihood of GI distress?
  16. Tell us about the topic of ‘fat adaptation’ to spare glycogen. From my reading and understanding, there is no good evidence that fat adaptation provides any benefit to endurance performance and it may even impair higher intensity performance (like going uphill) by not ‘sparing’ glycogen but rather by ‘impairing’ glycogen utilization…that apparent sparing may actually be a side effect of impaired utilization.
  17. How does caffeine ingestion interact with endogenous and exogenous substrate utilization?
  18. GI distress late in a race makes it difficult for some people to retain any calories they might swallow. Tell us about this interesting topic of ‘mouth sensing’ and what it might do for us in that situation.
We wrap up with a couple of focused action items:
1) What are the 2-3 biggest mistakes or misconceptions that you see endurance athletes make regarding carbohydrate and fueling for performance? 
2) What advice do you have for runners wanting to dial in their carbohydrate strategies (maximizing calories, best sources for them, etc.) for training and racing?