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



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Now displaying: September, 2015
Sep 29, 2015

My guests today are Dr. Sam Cheuvront and Dr. Robert Kenefick

  • Two of the world’s leading scientists in hydration and fluid homeostasis
  • Going in alphabetical order, 
    1. My first guest is Research Physiologist and Team Leader of the Thermal and Mountain Medicine Division at the US. Army Research Institute of Environmental Medicine (also known as USARIEM). His research includes the study of environmental and nutritional factors influencing human work performance. He is a leader in the fields of human fluid needs, dehydration assessment, heat stress mitigation, and exercise thermoregulation. He’s published over 100 -peer-reviewed papers and book chapters. Our first guest is Sam Cheuvront, PhD, RD
    2. My second guest is Principal Investigator in the Thermal and Mountain Medicine Division at USARIEM. He has published over 90 peer-reviewed manuscripts, book chapters AND reviews on fluid homeostasis and the physiological responses to environmental stress. He served as the president of the New England Chapter of the American College of Sports Medicine and received their Honor Award in 2012. He is also part of the Ultra Clan as an ultra marathon runner himself. Our second guest is Robert Kenefick, PhD.

My guests work for the U.S. Army. So, we must provide the disclaimer that "The views and/or opinions of Dr.'s Kenefick and Cheuvront are theirs personally and do not reflect the views or opinions of the U.S. Army or DoD."


This episode is the first in a two part series on fluids, hydration, and electrolyte physiology pertaining to ultra marathon running. We’re starting with the basics and progressing to specific application.

In this episode, you'll learn the answers to:

  1. What are the major body fluid and compartments and definitions the major relevant terms (de/eu/hyperhydration, hyper/hypovolemia)?
  2. What are the mechanisms/routes and quantities of water loss?
  3. How much water does a person need each day?
  4. Drinking to thirst - is it sufficient, like you hear commonly? (spoiler: NO!)
  5. How much salt is lost in sweat - only sodium? To what extent does this change throughout the time-course of an ultra marathon?
  6. What’s in sweat and what are ranges of rates and composition in running?
  7. During exercise, the majority of water gained is in the form of what we drink. But we have heard about getting water also from the breakdown of stored glycogen. Is this accurate?
  8. How can we expand our plasma volume?
  9. When do we need (and not need) an electrolyte-containing drink either during or after exercise?
  10. What is needed in an electrolyte drink beyond sodium?
  11. Hyponatremia; should it be a concern for most ultra marathon runners? 
  12. When does a runner need to consciously add sodium, beyond just following cravings?



Sep 24, 2015
My guest today is Jason Koop
  • Director of coaching for Carmichael Training Systems
  • He’s training everyone from the most famous in ultra running to people in your neighborhood
  • And…he’s an accomplished ultra runner himself…among many others, his finishing list includes Wasatch, Western States, Leadville, and Badwater.
In this episode we learn about
  1. Jason’s overall framework of prescriptions which emphasizes a progression from least event specific to most specific
  2. The optimal time frame to implement a full program
  3. Intervals to raise VO2max
  4. Setting pace and effort
  5. Total interval time of work for raising VO2max and for improving midrange performance
  6. Three broad phases of training and how much work/effort for workouts in those phases
  7. How many workouts per week?
  8. Factoring terrain (and elevation gain) to the workouts
  9. Does Koop use heart rate monitors?
  10. Detraining of VO2max closer to event with Koop’s approach?
  11. Approaches to choosing the number and spacing of races.
  12. Overtraining; over-fatigued/under-rested 
Plus, Jason gives you four pieces of advice that you can implement TODAY to improve your training and racing!
Sep 24, 2015
My guest today is Marty Hoffman, M.D.
  • Chief of Physical Medicine and Rehabilitation, VA Northern California Health Care System
  • Professor of Physical Medicine and Rehabilitation, University of California Davis
  • Research Director, Western States Endurance Run
  • Chief Medical Officer, Ultra Medical Team
  • Serves on several editorial boards, and is Editor-in-Chief, Wilderness & Environmental Medicine
  • Has published well over 100 peer reviewed research studies and 11 books or book chapters.
  • He is an accomplished ultra runner himself - He’s the 2008 Grand Master (50-59 age group) National Champion, USATF 100 Mile Trail Championship, Tahoe Rim Trail
In today’s episode:
  1. All about the history and current topics of research at Western States Endurance Runs (WSER).
  2. Hyponatremia at WSER
  3. Learn the answer to, "Is sodium supplementation necessary to avoid dehydration during prolonged exercise in the heat?”.
  4. What do we know today about the long term health of ultra-endurance runners? Is ultra marathon running bad for us AND WHY IT MAY NOT EVEN MATTER?
  5. Learn the most important take-home action items from research at WSER that you can put into practice TODAY!
  6. Find out how you can get involved in research at WSER.
Sep 23, 2015
This is the introduction episode, where I tell you about myself and the origin of Science of Ultra, a podcast for ultra marathon runners.