1. Integrative Physiology III: Exercise
Chapter 25
Integrative Physiology III: Exercise

2. About this Chapter
Overview of how major systems are involved in the metabolism for skeletal muscle contraction
How the extreme activities of exercise disrupt homeostasis
Focus on how the circulatory & respiratory systems integrate their responses to exercise demands
How exercise impacts health

3. Integration of Metabolism: Review of Roles of Systems in Muscle Contraction
Reactants
Transport
Conversions
Energy produced
Contractions
Respiration
Excretion
Endocrine
Nervous

4. Integration of Metabolism: Review of Roles of Systems in Muscle Contraction
Figure 25-1: Energy metabolism in skeletal muscle

6. Energy for Skeletal Muscle Contraction
ATP & ADP
Phosphocreatine
Aerobic paths
Anaerobic paths
(glycolytic metabolism)

7. Sustaining Muscle contractions: ATP Sources/Time
Phosphocreatine: Short bursts at maximal effort
Anaerobic: Intermediate duration intense effort
Aerobic: Long duration at reduced effort
Figure 25-2: Speed of ATP production compared with ability to sustain maximal muscle activity

9. Fat mass, adipose tissue and energy stores
Liver triglycerides = 450 kcal
Muscle triglycerides = 3000 kcal
Liver glycogen = 400 kcal
Muscle glycogen = 2500 kcal
Adipose tissue triglycerides = 120,000 kcal
Data for a 70 kg lean subject.

12. Hormonal regulation of Energy Source for ATP Production
(Huge body reserves – glucose 2000 & FFAs 70,000 Kcal)
Exercise intensity
Glucose
Fatty acids

13. Hormonal regulation of Energy Source for ATP Production
Metabolic Shifts
Glucagon
Cortisol
Epinep./NE GH
(insulin)

14. Hormonal regulation of Energy Source for ATP Production
Figure 25-3: Use of carbohydrates and fats with increasing exercise

15. Oxygen Consumption: Factors Sustaining or Limiting Exercise
O2 consumption:: to  exercise (measure w/Vo2 max)
Limiting factors:
O2 – cell availability, (O2 deficit)
O2 – transport to: mitochondria, to cell, to blood, or to lung

17. The Canadian Study of Health and Aging (CSHA) Clinical Frailty Scale (CFS).
The Canadian Study of Health and Aging (CSHA) Clinical Frailty Scale (CFS). Reproduced from Rockwood et al19 with permission of the publisher. Copyright © CMAJ, 2005.
Ekerstad N et al. Circulation. 2011;124:
Copyright © American Heart Association, Inc. All rights reserved.

18. Oxygen Consumption: Factors Sustaining or Limiting Exercise
Figure 25-4: Changes in oxygen consumption during and after exercise

19. Respiratory Ventilation: Exercise Induced hyperventilation
Feed forward Reflex: CNS
Feedback reflexes:
Motor sensors
Joint movement
Muscle contraction
Chemo sensors
O2 & CO2 levels
Synchronized w/ cardiac output
Plasma: [O2], [CO2] & [ pH]

20. Respiratory Ventilation: Exercise Induced hyperventilation
Figure 25-5: Changes in ventilation with submaximal exercise

21. Respiratory Ventilation: Exercise Induced hyperventilation
Figure 25-6: Changes in blood gas, partial pressures, and arterial pH with exercise

22. Cardiovascular Response to Exercise
Cardiac output
 5 to 35 L/min
Rate  2-3 X
Blood distribution
 muscles to 88% of all blood
 other tissues (except brain)

23. Cardiovascular Response to Exercise
Figure 25-7: Distribution of cardiac output at rest and during exercise

24. Homeostatic Balancing of Exercise: “Controlled Disruption”
Feed forward reflexes
Anticipate demand
Heart & lungs
Protective reflexes
Stretch damage
Temperature 
sweating
 peripheral
blood flow
redistribution
Blood pressure  constant

25. Homeostatic Balancing of Exercise: “Controlled Disruption”
Figure 25-8: Peripheral resistance and arterial blood pressure during exercise

26. Health Advantages of Regular Exercise: Quality of Life
 Cardiovascular disease risks: heart attack, stroke, high BP
 blood pressure
 LDL & triglycerides
 HDL  risks for diabetes
[blood glucose]
 obesity
 stress association
 immune function
(to a point)

27. Health Advantages of Regular Exercise: Quality of Life
Figure 25-9b: The effect of exercise on glucose tolerance and insulin secretion

28. Health Advantages of Regular Exercise: Quality of Life
Figure 25-10: Immune function and exercise

31. Summary
Exercise challenges a range of many systems involved in metabolism to produce maximal energy from various nutrient sources
Phosphocreatine most quickly produces ATP for muscle contraction while anaerobic glycolysis is intermediate
Aerobic ATP production is needed for endurance exercise

32. Summary
Ventilation and cardiac rate and output undergo huge changes which are anticipated by feed forward reflexes and protected by other reflexes to keep BP and temperature in homeostatic
Exercise reduces risk factors in some most common health problems: heart disease, obesity , diabetes, and stress