#124: Brent Ruby, PhD – The Human Ceiling of Energy Expenditure

In Podcasts by Danny Lennon1 Comment

Brent Ruby PhD, discusses his lab’s fascinating work on the upper limits of energy expenditure, markers of over-training vs. real-world performance, and the role of environment & temperature on performance and recovery.

Guest Bio

Brent Ruby, PhD

Brent is the director of the University of Montana Center for Work Physiology and Exercise Metabolism (WPEM). The center aims to mesh the research world with the operational field environment by combining study models that integrate the control of the laboratory with the hostilities of the field.

WPEM’s high tech $1.5 million facility opened it’s doors in 2008 and is a 3,550 sqft. facility which includes a biochemistry lab and a climate controlled environmental chamber that researches can manipulate temperature and humidity. The funds for the facility came from a U.S. Air Force grant, however the driving force which created the vision and made this possible was a choice made by Brent Ruby, the Director of WPEM. It was the choice to combine raw, rough field data with carefully controlled laboratory results to draw conclusions.

They have been able to collect samples from in-field race participants by parking trailside at prestigious events such as the Western States 100 race, the Badwater races and ultra marathons where the runners cover over 100 miles in grueling heat conditions. They have ventured with their needles and urine sample cups to the ice wall of Mount Ranier and Denali while in another study have been able to drive side by side, with trailer in tow, next to a group of college age males who rode their bicycles from Missoula to Colorado and back in 21 days.

The WPEM scientists study the stress hormones, enzyme RNA levels and stable isotope tracers to draw a more clear picture of what happens to the human body under great physical and or environmental stress. This data serves as groundbreaking science to gauge the limits of the human energy expenditure: The Human Ceiling.

In this episode we discuss:

  • Energy demands on long-duration, endurance work and insights into the “human ceiling” of energy expenditure
  • Assessing energy expenditure
  • Markers of over-training vs. actual impact on performance in “real world” settings
  • Balancing the need for tightly controlled trials with designing studies that better simulate real world scenarios in practice
  • The role of environment during the recovery phase and glycogen resynthesis
  • Are sports nutrition products and supplements actually any better than fast food?
  • Hydration, water turnover and heat/cold stress
  • Why performance tanks in the heat: skin temperature versus core body temperature

Links & Resources:


  1. Pingback: SNR #208: Herman Pontzer, PhD – Constrained Energy Expenditure Model & the Evolutionary Biology of Energy Balance | Sigma Nutrition & Performance

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