Limits of Human Energy Expenditure

​

What are the limits to sustained energy expenditure? Is our physical capacity for endurance ultimately limited by energy? Using the doubly-labelled water method, we are measuring total energy expenditure (TEE) in ultra-endurance athletes, both during ultra events and a 10-day baseline period of normal life and training. Together with basal metabolic rate, or BMR (including measurements taken at MCLA via indirect calorimetry), this will allow us to calculate metabolic scope (TEE/BMR). We are testing Westerterp (2001) and Thurber et al's. (2019) hypothesis that sustained metabolic scope is limited to ~2.5x basal metabolic rate.  Additionally, these data will further elucidate the curvilinear relationship between event duration and metabolic scope. 

​

Collaborators: Dr. Herman Pontzer and Pontzer Lab, Duke University

Undergraduate research assistants: Marie Balan, MCLA

​

​

Variation in sweat gland density

​

Humans have ten times the eccrine sweat gland density of other apes, an adaptation that probably evolved to help our ancestors forage, scavenge and hunt in hot conditions. Humans today have lots of variation in sweat gland density. How is this variation patterned? And does this variation matter- does having higher or lower sweat gland density correlate with sweat production or ability to dissipate heat? We sampled active eccrine gland data from ~80 volunteers of varying geographic ancestries and childhood climates to investigate these questions. Results are published here.  Plans are in progress to build a thermal room in the MCLA Human Performance Lab for continued testing. 

​

Collaborators: Dr. Jason Kamilar, Dr. Daniel Lieberman, Dr. Brigitte Holt, Dr. Alexander Gerson, Dr. Michael Busa

Undergraduate research assistants: Jennifer Marino, Kalina Bergman 

​