Lecture 2 - Kin 2000
KIN2000 Physical Activity & Health - Lecture 2: Why is Physical Activity Important?
Page 1: Course Introduction
Course Name: KIN2000
Topic: Physical Activity & Health
Lecture Focus: Why is Physical Activity Important?
Page 2: Quick Reminders
Use your Teaching Assistant (TA) for assistance.
For communication and group work: Brightspace → Communications → Groups.
Assignment Deadlines:
1st Assignment due: January 16th (cannot be submitted prior)
2nd Assignment due: January 21st
Submission format: Avoid using Pages.
Page 3: Understanding Physical Activity
Physical Activity Defined:
Definition: Any bodily movement produced by the contraction of skeletal muscles that results in a substantial increase in caloric requirements over resting energy expenditure.
Page 4: Muscle Contraction Overview
Muscle Contraction Emphasis:
ATP (Adenosine Triphosphate) is required for muscle contraction.
Structural Anatomy of Muscle Fibers:
Sarcomere components:
Z line
M line
Myofibrils consisting of:
Actin (thin filament)
Myosin (thick filament)
Process of Muscle Contraction:
Resting State: Muscle relaxed state.
Calcium Release: Calcium ions bind to myosin heads, allowing them to attach to actin filaments.
Power Stroke: Myosin heads pivot, pulling actin filaments inward.
ATP Role: ATP binds to myosin to detach it from actin, resetting for another cycle.
Page 5: What is ATP?
Structure of ATP:
Composed of: Adenine, Ribose, and three Phosphate groups (Triphosphate).
Page 6: ATP and Energy
Hydrolysis Reaction:
Reaction: ATP + H₂O → ADP + Pᵢ + Energy.
ATP generates energy for muscle contractions:
Energy utilization in mechanical work.
Reactions in muscle contraction detailed using the thin (actin) and thick (myosin) filament interactions during contraction cycles.
Page 7: Functions of ATP
ATP uses include the following:
Synthesis of genetic materials and cellular macromolecules.
Muscle movement, transportation of molecules, and conversion to electrical energy.
Page 8: ATP Storage and Availability
ATP Storage Facts:
Muscle stores approximately 6 mmol ATP per kg muscle.
Rates of ATP Breakdown:
Light Exercise: 0.4 mmol/kg/s for ~15 seconds.
Max Exercise: 3.7 mmol/kg/s for < 2 seconds.
Limited ATP stores require real-time replenishment during extended exercise.
Page 9: Replenishment of ATP
ATP Sources:
ATP-PC System (Anaerobic)
Carbohydrate Metabolism (Anaerobic)
Carbohydrate Metabolism (Aerobic)
Fat Metabolism (Aerobic)
Page 10: ATP-PC System
Stored Phosphocreatine (PCr) Usage:
Reaction: ATP + H₂O → ADP + Pᵢ + Energy.
System Mechanics: PCr + ADP → ATP + Cr.
Characteristics: Rapidly depletes within about 20 seconds during high-intensity activity (known as the Anaerobic-Alactic system).
Page 11: Metabolism Overview
Breakdown of Food Components:
Proteins → Amino Acids.
Carbohydrates → Monosaccharides (e.g., Glucose).
Fats → Glycerol and Fatty Acids.
Pathways in Energy Production:
Glycolysis of glucose to pyruvate.
Transfer of electrons creates ATP through oxidative phosphorylation in mitochondria.
Page 12: Glycolysis (Anaerobic Metabolism)
Reaction: Glucose + 2ADP + 2Pᵢ + 2NAD⁺ → 2 Pyruvate + 2ATP + 2NADH + 2H₂O + 2H⁺.
Function: Fast glycolysis that allows for rapid energy release for muscle activity for up to 2 minutes.
Page 13: Aerobic Metabolism of Carbohydrate
Overall Summary Equation:
Glucose + 6O₂ + 32ADP + 32Pᵢ → 6CO₂ + 6H₂O + 32ATP.
Mechanisms:
Pyruvate enters mitochondria.
Oxygen participates in ATP resynthesis.
Page 14: Metabolism Summary
Carbohydrate, Protein, and Fat Metabolism processes recapped:
Glycolysis, citric acid cycle, and oxidative phosphorylation.
Page 15: Aerobic Fat Metabolism
Fat Breakdown Equation for Palmitate:
Reaction: Palmitate + 8CoA + 7NAD⁺ + 7FAD + 7H₂O → 8 Acetyl CoA + 7NADH + 7FADH₂ + 7 H⁺.
ATP Yield for Palmitate: Approximately 108 ATP molecules produced from complete oxidative metabolism.
Page 16: Aerobic Metabolism Characteristics
Oxidative phosphorylation is capable of sustaining ATP needs indefinitely whereas anaerobic mechanisms cannot.
As oxidative phosphorylation becomes predominant, reliance on anaerobic systems decreases, which allows prolonged activity.
Page 17: Percent Energy System Capacity
Energy System Capacity Charts demonstrated various time frames concerning energy system contributions:
0-10 seconds: Immediate ATP-PC system dominance.
Up to 2 minutes: Switch from anaerobic to aerobic systems dependent on exercise duration.
Page 18: Power and Capacity Charts
Energy systems capability for sustained exercise illustrated, highlighting the endurance of aerobic mechanisms as opposed to anaerobic pathways.
Page 19: Energy Supply Diagram
Diagram connecting energy supply sources to physical activity detailing pathways for ATP, PCr, oxygen uptake, and mitochondrial activity.
Page 20: Oxygen Uptake
Definition and Importance of Oxygen Uptake:
Oxygen uptake necessary for aerobic metabolism.
Process: Breathed in oxygen → transported to blood → delivered to muscles for ATP production.
Page 21: Oxygen Demand & Uptake Metrics
Definitions:
= rate of O₂ uptake.
Absolute = mL/min, Relative = mL/kg/min.
Resting = 3.5 mL/kg/min equivalent to 250 mL/min in a 70 kg male.
Page 22: Maximal Oxygen Uptake
Definition of max:
Greatest amount of O₂ utilized at the cellular level by the body.
Indicator of cardiorespiratory fitness.
Page 23: Maximal Oxygen Uptake Charts
Comprehensive charts detailing max values and health fitness levels by age and fitness categories (from low, fair, average, good to elite).
Page 24: All-Cause Mortality & CRF
Discussion of Cardiorespiratory Fitness (CRF) as a Clinical Vital Sign:
Improvement of health outcomes via increased CRF.
Page 25: Health Benefits of CRF
Correlation between high CRF and lower incidence of various diseases and conditions.
Page 26: Importance of Physical Activity
Key roles of physical activity include:
Attenuation of chronic disease prevalence and mortality.
Improvements in mental and physical health.
Better quality of life and independence in older populations.
Page 27: Chronic Disease Definition
Definition and Characteristics:
Non-communicable diseases; non-contagious, long duration, and progress slowly due to genetics, environment, or lifestyle factors.
Page 28: Global Causes of Death
Trends in causes of death shift from communicable to non-communicable disease due to improved treatment and management.
Page 29: Burden of Chronic Disease Studies
Overview of Global Burden of Disease findings and shifts in health priorities.
Page 30: Chronic Disease Statistical Insights
Definition and importance of Disability-adjusted life-years (DALY) to measure overall health burden.
Page 31: Changes in DALY Rates (1990 vs. 2023)
Analysis of changing leading causes of death over recent decades.
Page 32: Disease Burden Updated Analysis
Overview of health gain milestones and ongoing challenges.
Page 33: Leading Causes of Death Charts
Detailed graphical representations of leading health challenges across different years.
Page 34: Prevalence of Chronic Diseases in Older Adults
Prevalence statistics highlighting the significant incidence of chronic diseases among Canadian adults aged 65+.
Page 35: Modifiable Risk Factors for Chronic Diseases
Key behavioral, metabolic, and environmental factors impacting chronic disease incidence.
Page 36: Global Trends & Future Projections
Updates on trends regarding chronic diseases projected increases in the coming decades.
Page 37: Health Impact of Regular Physical Activity
Overview of benefits pertaining to both mental and physical health as a result of active lifestyles.
Page 38: Role of PA in Reducing Chronic Diseases
Impact of regular physical activity in regulating conditions like diabetes, cardiovascular disease, and obesity.
Page 39: Exercise Effects on Health Metrics
Evidence supporting physical activity for improved health outcomes and reduced mortality rate.
Page 40: Community Health Recommendations
WHO guidelines emphasizing the importance of regular physical activity for global health initiatives.
Page 41: Physical Activity Guidelines for Older Adults
Specific recommendations targeting older adults to mitigate risks associated with sedentary habits.
Page 42: Conclusion/Closing Remarks
Regular physical activity is not only beneficial but essential in lowering the risk of many chronic diseases and improving overall health and well-being.