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Human Energy Systems. NFSC 303. You will not be required to do the mathematical conversions from one for of energy to another (p. 83-85 of textbook). Energy Balance = “energy in” vs. “energy out” Energy in: Energy out: . How do we measure Calories?. Direct Calorimetry: In food:

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Energy Balance = “energy in” vs. “energy out” from one for of energy to another (p. 83-85 of textbook)

Energy in:

Energy out:


How do we measure calories
How do we measure Calories? from one for of energy to another (p. 83-85 of textbook)

  • Direct Calorimetry:

    • In food:

    • In humans:

  • Indirect Calorimetry:

  • Newer: IDEEA device

    • Intelligent Device for Energy Expenditure and Activity

    • Records body motions every second for 24 hours.


Components of energy expenditure
Components of Energy Expenditure from one for of energy to another (p. 83-85 of textbook)

  • Energy to support basal metabolism: BEE

  • Energy to support physical activity: TEE

  • Energy to process food: TEF


Energy to support basal metabolism
Energy to Support Basal Metabolism from one for of energy to another (p. 83-85 of textbook)

  • BEE = Basal Energy Expenditure

  • (Calculated from BMR = Basal Metabolic Rate)

    • Measured in standard state (no food/exercise for 12 hours; measurement taken right after waking, resting at a comfortable temperature)

    • REE/RMR = Resting Energy Expenditure or Resting Metabolic Rate: similar numbers (not standard state)


  • Primary factors affecting from one for of energy to another (p. 83-85 of textbook)BMR/BEE:

  • Other factors: growth, fever, ambient temp., pregnancy, smoking, disease, age, BSA, kcalorie intake


To estimate from one for of energy to another (p. 83-85 of textbook)BEE:

  • Rough estimate: Body weight in pounds X 10

  • More accurate:

    Men:

    Women:

    Example:


Energy to support physical activity
Energy to Support Physical Activity from one for of energy to another (p. 83-85 of textbook)

  • TEE = Thermic Effect of Exercise


Energy needed to process food
Energy Needed to Process Food from one for of energy to another (p. 83-85 of textbook)

  • TEF = Thermic Effect of Food


Total Daily Energy Expenditure (kcals) from one for of energy to another (p. 83-85 of textbook)

TEE

TEF

Remember: BMR is measured 12 hours after any physical exercise and in a fasted state.

BEE


Wide difference in metabolic rates due to genetics
Wide difference in metabolic rates due to genetics... from one for of energy to another (p. 83-85 of textbook)

  • But within our individual range…

    • lowest would be achieved via

    • highest would be achieved with


Fueling activity

Fueling Activity from one for of energy to another (p. 83-85 of textbook)


  • Exogenous from one for of energy to another (p. 83-85 of textbook) fuels: from outside the body

    • dietary protein, CHO, and fat

  • Endogenous Fuels: from within the body

    • importance increases in times of inadequate kcalories or CHO intake


Energy metabolism all processes involved in the production storage and use of energy
Energy Metabolism: from one for of energy to another (p. 83-85 of textbook)All processes involved in the production, storage, and use of energy

  • As macronutrients are broken down, E from the breakage of bonds is:


Atp adenosine triphosphate

A-P from one for of energy to another (p. 83-85 of textbook)~P~P

High-energy bonds “store” energy

Cleaved to release E for

A-P~P /P = ADP

A-P/ P = AMP

To regenerate ATP, we need a source of P with high energy bonds:

ADP + P

AMP + 2P

These high-energy bonds will come from:

ATP: Adenosine Triphosphate


Phosphocreatine pcr
Phosphocreatine: PCr from one for of energy to another (p. 83-85 of textbook)

  • High-E molecule - helps maintain a steady supply of ATP for short bursts of energy

  • To keep regenerating ATP:


Metabolic pathways
Metabolic Pathways from one for of energy to another (p. 83-85 of textbook)

  • Take place in the cytosol and mitochondria of the cell


  • Anabolic from one for of energy to another (p. 83-85 of textbook) Pathways:

  • Catabolic Pathways:

  • Anaerobic:

  • Aerobic:


Overview of pathways

Overview of Pathways from one for of energy to another (p. 83-85 of textbook)


Anaerobic metabolism glycolysis
Anaerobic Metabolism: from one for of energy to another (p. 83-85 of textbook)Glycolysis

  • ONLY carbohydrate can do it.


Anaerobic metabolism glycolysis1
Anaerobic Metabolism: from one for of energy to another (p. 83-85 of textbook)Glycolysis

  • Glucose (from glycogen) is “split” for E

    • It is only partially metabolized – will need oxygen to metabolize it completely.

  • Primary source of E during _____________ (when O2 availability is low)

  • Takes place in the cytosol of the cell


Aerobic metabolism krebs cycle and electron transport system ets
Aerobic Metabolism: Krebs Cycle and Electron Transport System (ETS)

  • Can metabolize fat, carbohydrate (finish the job) and some protein.


So to fuel activity, we need ATP. System (ETS)

ATP is generated by metabolizing our fuel sources: carbohydrate, fat, and some protein.

So how much of each fuel do we use during exercise? (What’s the fuel mix for a given exercise?)


Primary exercise fuels cho and fat
Primary Exercise Fuels: System (ETS)CHO and FAT

  • Carbohydrate from ______________

  • Fat from ________________

    Remember: only CHO can be burned when oxygen availability is low


Fuel sources used during exercise depend on
Fuel sources used during exercise Depend on: System (ETS)

  • Intensity of activity

  • Duration of activity

  • Fitness level of the individual

  • Macronutrient and kcalorie content of diet


  • Fuel Sources: System (ETS)

    • Immediate – ATP/PCr system

    • Anaerobic – O2 not required.

      • Glycolysis alone can support muscle contraction for ~ 30 seconds to 2 minutes.

    • Aerobic – O2 required


When exercise begins
When Exercise Begins… System (ETS)

  • O2 hasn’t gotten to muscles yet

  • ATP/CP during first seconds

  • Mostly Anaerobic for several minutes

  • Then, aerobic (along with anaerobic) for the rest of exercise time.


Fuel sources used during exercise depend on1
Fuel sources used during exercise Depend on: System (ETS)

  • Intensity of activity

  • Duration of activity

  • Fitness level of the individual

  • Macronutrient and kcalorie content of diet


Exercise intensity
Exercise Intensity System (ETS)

  • VO2Max

  • THR range

  • RPE

  • Mild Intensity Exercise (walking)

    • ____________________ are the predominant fuel for ATP production (Krebs and ETS)

      • (~60% FA and 40% CHO)


  • Moderate Intensity Exercise (ie. Jogging, aerobics) System (ETS)

    • Rely on

    • Therefore, more _________ is used

      • (e.g. ~50% CHO/50% Fat)

    • The longer the duration, the greater use of ___________ as fuel

    • (for exercise lasting several hours, 60-70% energy can be supplied by fat).



Fuel sources used during exercise depend on2
Fuel sources used during exercise Depend on: System (ETS)

  • Intensity of activity

  • Duration of activity

  • Fitness level of the individual

  • Macronutrient and kcalorie content of diet


Exercise duration
Exercise Duration System (ETS)

FAT

CHO

rest

TIME


Fuel sources used during exercise depend on3
Fuel sources used during exercise Depend on: System (ETS)

  • Intensity of activity

  • Duration of activity

  • Fitness level of the individual

  • Macronutrient and kcalorie content of diet


Fitness status
Fitness Status System (ETS)

  • Increased fitness status:

  • Increased:


  • Training Effects of Aerobic Exercise: System (ETS)

    •  LDL (“bad”)cholesterol,  HDL (“good”)cholesterol

    • strengthened heart, lungs

    • curbed appetite

    •  metabolic rate…


  • Effects of Strength Training System (ETS)

    •  LDL (“bad”) cholesterol

    •  constipation, diverticulosis, hemorrhoids, and poss. Colon CA

      • speeds waste through colon

    • stronger bones


Fuel sources used during exercise depend on4
Fuel sources used during exercise Depend on: System (ETS)

  • Intensity of activity

  • Duration of activity

  • Fitness level of the individual

  • Macronutrient and kcalorie content of diet


Diet System (ETS)

  • High fat diet

  • Lower fat, mod. prot, high CHO diet


Fatigue
Fatigue System (ETS)

  • The inability to continue exercising at a desired level of intensity

  • Inability to produce ATP to meet demands

  • Other factors

  • We’ll address fatigue in later sections.


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