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3/13/2012. 2. . Performance Modeling. Objectives/Applications:Demonstrate the psycho-physiological costs
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1. 3/13/2012 1 Warfighter Performance Modeling: Metabolic Fatigue
2. 3/13/2012 2 Performance Modeling Objectives/Applications:
Demonstrate the psycho-physiological costs & benefits of novel products or doctrine.
Reduce overall program risk through Simulation Based Acquisition.
Approach:
Develop model(s) to estimate the effects of operational stress on psycho/physiological state.
Integrate these models into individual combatant models (e.g., IWARS)
Limitations:
Applicability limited by development stage of psycho-physiological models
3. 3/13/2012 3 Metabolic Fatigue Definition:
Failure to maintain work level due to under-nutrition, carbohydrate depletion or slowing of metabolic machinery.
Cause:
Depletion of usable energy (ATP) due to:
Rates of ATP production not meeting rates of ATP utilization due to:
1. Depletion of key metabolic fuels
2. Slowed biochemical reaction rates
3. Extremely high levels of physical activity
4. 3/13/2012 4 Key Metabolic Fuels Very Short Term (seconds):
Phosphocreatine
Stored ATP
Muscle Glycogen
Prolonged (hours):
Carbohydrates (Muscle Glycogen, Blood Glucose, Liver Glycogen)
Fatty Acids (from adipose and muscle tissue)
Extended Duration (days):
Carbohydrates (very limited availability)
Fatty Acids (from adipose tissue)
Ketones
Proteins
5. 3/13/2012 5 Dynamic Nutrition Model (DYNUMO) Ultimate Objective:
Model the effects of macronutrient intake and physical activity on metabolic fuel status during military operations.
General Approach:
Develop algorithms based on known physiology and biochemistry
Test using available data
Iterative Approach:
Currently limited to “prolonged” (several minutes to several hours), steady state activity, with and without macronutrient intake.
6. 3/13/2012 6 DYNUMO Inputs & Outputs
7. 3/13/2012 7 Limiting Metabolic Fuels for Performance Muscle glycogen is the primary limiting factor for physical performance (under steady state conditions).
Blood glucose is the primary limiting factor for cognitive performance and affects physical performance in some cases.
Liver glycogen is a reservoir for blood glucose.
Fatty Acid utilization helps determine glycogen and glucose utilization in muscle while, at the whole-body level, glucose availability helps determine fatty acid release from adipose tissue.
8. 3/13/2012 8 Model Schematic
9. 3/13/2012 9 Metabolic Processes
10. 3/13/2012 10 Testing(Simulation of Coyle et al., 1986)
11. 3/13/2012 11 Testing(Simulation of Coyle et al., 1986)
12. 3/13/2012 12
13. 3/13/2012 13 DYNUMOCollaborations & Support Modeling and Analysis Team, U.S. Army Soldier Systems Center, Natick, MA. POC: Mr Paul Short (paul.short@natick.army.mil, 508-233-4256)
Combat Feeding Program, U.S. Army Soldier Systems Center, Natick, MA
Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA
U.S. Department of Defense Combat Feeding, Research and Engineering Program
14. 3/13/2012 14 Summary Models of individual combatant behavior may be used for mission planning & analysis, soldier system development & analysis, and simulation-based acquisition.
DYNUMO may be used within such models to estimate the effects of warfighter activity and nutrient intake on metabolic aspects of fatigue. DYNUMO is currently capable of estimating metabolic status and glucose requirements during prolonged, steady-state physical activity, with and without macronutrient intake.