2. Lecture 11b-26 March 2018
This lecture is based largely on CHAPTER 23 IN KRAUSE'S FOOD NUTRITION AND DIET THERAPY (ON RESERVE IN LIBRARY) AND CHAPTERS 7,8,9 IN ROLFES ET AL.

3. Final exam-120 multiple choice-120 marks
from vitamins to end of course
-4 short answer questions-15 points each for a total of 60 points
covers whole course
-3 hours- 180 marks

4. Lecture 11 Outline Energy production ATP Anaerobic pathway
Metabolic aspects of Nutrition and fitness/Sports Nutrition
Energy production
            ATP
            Anaerobic pathway
            Aerobic pathway
            Energy continuum
            Sources of fuel
           

5. Outline of lecture 11
Energy production
Substrate choice
Intensity
         Duration
          Effect of training
          Diet

6. Outline of lecture 11
Nutritional Requirements
            Fluid
                 Fluid Balance
                 Fluid Absorption
Factors affecting fluid absorption
                 Requirements
                         Short duration
                         Endurance

7. Outline of lecture 11
Nutritional Requirements
           Carbohydrate
                        Types of carbohydrate
                        Pre-event
                        During event
                        Post-event

8. Outline of lecture 11
Nutritional Requirements
           Protein
                Endurance
                Resistance Exercise
                Amino acid supplementation

9. Outline of lecture 11
Nutritional Requirements
            Lipid
            Minerals
                        Iron
                        Calcium
            Vitamins
                        Anti-oxidant vitamins and B- carotene
                       C
                        E
                        B vitamins

10. Outline of lecture 11
Regulation of metabolism

11. Energy production
Energy continuum
All pathways can produce ATP
At the beginning of any exercise whatsoever anaerobic metabolism is in place to produce ATP
If the person continues to exercise at a moderate level for a prolonged period then the aerobic pathway will become the predominant pathway for energy production (eg marathon run)
                                   

12. Energy production
Energy continuum
If the person continues to exercise for a short period of high power and high intensity then the anaerobic pathway will become the predominant pathway for ATP energy production(eg 100 metre sprint)
Production of ATP is therefore a continuum that depends on the:
            -availability of oxygen
            -the capacity for intensity of the exercise
            -the capacity for the duration of the exercise

13. Energy production
Energy continuum
There is an inverse relation between the capacity for intensity and the capacity for the duration of the exercise
-one cannot perform high intensity exercise over a long period of time
-the duration increases as the intensity drops and as the intensity of the exercise increases the duration of that exercise drops

14. Energy production
Energy continuum
-the aerobic pathway cannot tolerate the same level of intensity as the duration increases due to the decreased availability of oxygen and the production of lactic acid

17. Energy production
Sources of fuel
        as the duration increases more energy is obtained from fat (fatty acids) and as the duration decreases and the intensity increases more energy is obtained from carbohydrate
        carbohydrate is obtained from dietary carbohydrate, glycogen or amino acids (amino acids can be synthesized to glucose-this process is known as gluconeogenesis)
                            
                                                           

18. Energy production
Sources of fuel          
Kreb’s cycle-alanine is the main amino acid contributing to the Krebs cycle
  carbon units of glucose contributing to the Krebs cycle
-2 unit carbons of fatty acids contributing to the Kreb’s cycle
                                                           

19. Energy production
Sources of fuel  
        
Kreb’s cycle
-all of these substrates are used most of the time however the intensity and duration of the exercise dictates the relative rates of substrate utilisation
                            
                                                           

20. Energy production
Substrate choice
Intensity- high intensity must rely on carbohydrate
Because oxygen is not available for high intensity exercise glycogen must be utilized
Glycogen catabolism is much higher than with aerobic activity times faster (2 ATP versus ATP)
                            
                                                           

21. Energy production
Substrate choice
Intensity-Hockey, basketball for eg favour higher glycogen utilization rates than marathon running while moderate intensity exercise favours 50/50 split of (glycogen)/(glucose- lipid) use
                            
                                                           

22. Energy production Substrate choice
        Low intensity exercise like walking is entirely aerobic and most of the ATP comes from lipid
Fat yields 4.65 kcal / L of oxygen consumed vs  for carbohydrate a yield of 5.01 kcal/L of oxygen consumed
-thus in longer term exercise carbohydrate use is favoured relative to low intensity exercise
However, once the glycogen stores are depleted then that is the end of the high intensity exercise as carbohydrate utilisation is critical to lipid utilisation
                    
                                                           

23. Energy production
Substrate choice
Duration-the longer the event the greater the proportion of lipid used to produce ATP  
                        -consequently the lower the amount of lactate produced
Effect of aerobic training-increase number of mitochondria and activity of ATP producing enzymes-this impacts efficiency of both carbohydrate and lipid utilisation which ever is chosen
                            
                                                           

24. Energy production
Substrate choice
Diet-dictated by fuel utilization for a particular event
      -high intensity requires more carbohydrate in the diet
       -lower intensity requires more lipid in the diet
         however do not consume a high fat diet- crowd out carbs and run the risk of heart disease
                            
                                                           

25. Class exercise 
Explain the effects of exercise intensity, duration and training on substrate utilisation.                         
                           
                            
                                                           

26. Break                           
                           
                            
                                                           

27. Nutritional Requirements Fluid Fluid Balance
Important for maintaining blood flow which in turn is important for supplying blood to skin and hence temperature control
75 percent of energy goes out as heat-therefore must sweat
regulated by kidney, sweat loss, feces, respiration and fluid intake
important to consume sodium and water to replace water lost as sweat-thus blood sodium is maintained and therefore so are hormone levels which limit the rate of urine production
                           
                            
                                                           

28. Nutritional Requirements
Fluid Absorption
         Factors affecting fluid absorption
                   -glucose and sodium travel across intestine on same carrier
                           
                            
                                                           

29. -if several heats before actual race this can be problem for hydration
Nutritional Requirements
Fluid Requirements
      Short duration
-if several heats before actual race this can be problem for hydration
- plain water dilutes the blood, increases urination and results in dehydration
       Endurance
-plain water lowers blood glucose concentrations thus increasing the demand on muscle glycogen
                           
                            
                                                           

30. Carbohydrate Types of carbohydrate
Nutritional Requirements
Carbohydrate
      Types of carbohydrate
After glycogen runs out must use gluconeogenesis to maintain blood glucose levels
Glycogen loading is important-eg pasta diet some have suggested complex carbs are better at glycogen loading in muscle than are simple carbs but this is debatable
                           
                            
                                                           

31. Maintains adequate blood glucose levels for event During event
Nutritional Requirements
Carbohydrate
Pre-event
             Takes care of hunger
             Maintains adequate blood glucose levels for event
          During event
              Maintains blood glucose and delays fatigue
          Post-event
              Builds glycogen up in muscle after depletion
                           
                            
                                                           

32. Less required than for resistance events Resistance Exercise
Nutritional Requirements
Protein
       Endurance
               Less required than for resistance events
       Resistance Exercise
                 More required than for endurance events
                                                -muscle mass issue
                 
                           
                            
                                                           

33. Amino acid supplementation
Nutritional Requirements
Protein
Amino acid supplementation
A waste of time- eat more calories in accordance with Canada’s food guide to meet increased energy demands and this will easily meet added protein/amino acid requirements
Can lead to dehydration, loss of urinary calcium, weight gain and stress on the kidney and liver
                           
                            
                                                           

34. -supplies essential fatty acids
Nutritional Requirements
Lipid
         -supplies essential fatty acids
         -important energy source during endurance exercise
          -less important as an energy source for high intensity exercise
                           
                            
                                                           

35. Class exercise
How do the 6 nutrient classes work together to allow:
Aerobic exercise
Anaerobic exercise
                           
                            
                                                           

36. Break                           
                           
                            
                                                           

37. -oxygen carrying-hemoglobin and myoglobin
Nutritional Requirements
Minerals
          Iron
              -oxygen carrying-hemoglobin and myoglobin
              -part of electron transport chain-ATP
          Calcium
               -bone mass
                           
                            
                                                           

38. Anti-oxidant vitamins and b-carotene, vitamin C and E
Nutritional Requirements
Vitamins
    Anti-oxidant vitamins and b-carotene, vitamin C and E
-exercise produces increased amount of  lipid peroxides and free radicals-damage muscle
-supplements are not required-no evidence that they improve performance
         B vitamins
            -important co-enzymes in energy production
           -B12-supplement required in strict vegans
                        
                           
                            
                                                           

39. Regulation of Metabolism
Oxygen supply
As intensity of exercise increases the oxygen supply becomes limiting-with training one can supply more oxygen
Substrate supply
Availability of co-enzymes
Hydration
Mechanisms described for each of the nutrient classes
                           
                            
                                                           

40. Class exercise  
What is the major direction of metabolism
during exercise?
after exercise?   
Why ?