Presentation Type
Poster Presentation
Category
STEM (science, technology, engineering, mathematics)
Abstract/Artist Statement
Among the highest empirically reported doubly labeled water (DLW) derived total energy expenditure (TEE) and water turnover (rH2O) values occur during 161km (100-mile) ultra-endurance events. TEE and rH2O of ultra-endurance events surpassing 161km present an anomalous physiological stressor to further detail human endurance limits. PURPOSE: To quantify TEE and rH2O during a multi-day ultra-endurance event. METHODS: Two runners (female [R1], male [R2]) completed 322 km following DLW (2H218O) consumption. Urinary isotopic elimination rates were used to calculate TEE and rH2O. Race-provided GPS monitors measured duration, moving time, and non-activity time. RESULTS: R1 finished in 73.6h (50.3h moving, 23.3h resting) at an overall average speed of 1.3 m·s-1. In-race TEE for R1 was 123.9 MJ (29,376 kcals) and 35.5 MJ·d-1 (8,408 kcals·d-1, 5.6x basal metabolic rate [BMR]) when expressed as a 24h rate. In-race rH2O for R1 was 35.21 L (10.08 L.d-1). R2 finished in 89.9h (43.0h moving, 46.9h resting) at an overall average speed of 1.0 m·s-1. In-race TEE for R2 was 164.2 MJ (38,909 kcals) and 41.1 MJ·d-1 (9,737 kcals·d-1, 5.0x BMR) when expressed as a 24h rate. In-race rH2O for R2 was 47.50 L (11.89 L.d-1). CONCLUSIONS: Multi-day ultra-endurance events are an exceptional feat of human endurance as evidenced by large overall TEE and rH2O. However, the non-activity time (non-ambulation, sleep) inherent to multi-day ultra-endurance events may dilute 24h TEE when compared to 161km distances. Though elevated, rH2O may vary by environmental conditions. Thus, the metabolic ceiling of sustained human endurance will depend on event and conditions specifics.
Mentor Name
Dustin Slivka
Total Energy Expenditure and Water Turnover During a 335 km Mountain Ultramarathon
UC North Ballroom
Among the highest empirically reported doubly labeled water (DLW) derived total energy expenditure (TEE) and water turnover (rH2O) values occur during 161km (100-mile) ultra-endurance events. TEE and rH2O of ultra-endurance events surpassing 161km present an anomalous physiological stressor to further detail human endurance limits. PURPOSE: To quantify TEE and rH2O during a multi-day ultra-endurance event. METHODS: Two runners (female [R1], male [R2]) completed 322 km following DLW (2H218O) consumption. Urinary isotopic elimination rates were used to calculate TEE and rH2O. Race-provided GPS monitors measured duration, moving time, and non-activity time. RESULTS: R1 finished in 73.6h (50.3h moving, 23.3h resting) at an overall average speed of 1.3 m·s-1. In-race TEE for R1 was 123.9 MJ (29,376 kcals) and 35.5 MJ·d-1 (8,408 kcals·d-1, 5.6x basal metabolic rate [BMR]) when expressed as a 24h rate. In-race rH2O for R1 was 35.21 L (10.08 L.d-1). R2 finished in 89.9h (43.0h moving, 46.9h resting) at an overall average speed of 1.0 m·s-1. In-race TEE for R2 was 164.2 MJ (38,909 kcals) and 41.1 MJ·d-1 (9,737 kcals·d-1, 5.0x BMR) when expressed as a 24h rate. In-race rH2O for R2 was 47.50 L (11.89 L.d-1). CONCLUSIONS: Multi-day ultra-endurance events are an exceptional feat of human endurance as evidenced by large overall TEE and rH2O. However, the non-activity time (non-ambulation, sleep) inherent to multi-day ultra-endurance events may dilute 24h TEE when compared to 161km distances. Though elevated, rH2O may vary by environmental conditions. Thus, the metabolic ceiling of sustained human endurance will depend on event and conditions specifics.