Exercise Physiology

version from 2017-10-28 19:30

Section 1

What is the efficiency of substrate metabolism 40% of substrate energy--> ATP. 60% of substrate energy--> heat.
How does a calorimeter work Heat production increases with energy production – Can be measured in a calorimeter – Water flows through walls of calorimeter – Body temperature increases water temperature (thermometer accuracy: 0.01°C)
Pros of direct calorimetry – Accurate over (long!) time – Good for resting metabolic measurements
Cons of direct calorimetry – Expensive, slow – Exercise equipment adds extra heat – Sweat creates errors in measurements – Not practical or accurate for exercise
What is the respiratory exchange ratio (RER)VCO2/VO2.
What is the equation for pure carbohydrate oxidation (glucose) O2 + C6H12O6 --> 6 CO2 + 6 H2O (+32 ATP). RER = 6 CO2 / 6 O2 = 1.0
What is the equation for pure fat oxidation (palmitic acid)23 O2 + C16H32O2 --> 16 CO2 + 16 H2O (+129 ATP) RER = 16 CO2 / 23 O2 = 0.7
Each litre of oxygen consumes makes available what amount of energy 5 kcal
If we are using 100% fats to derive energy, what is the RER (respiratory exchange ratio)0.71
For each litre of oxygen consumed when using fat , how much energy becomes available 9 kcal/g
For each litre of oxygen consumed when using carbohydrates, how much energy becomes available 4 kcal/g
How much energy does pure carbohydrate oxidation require32 ATP
How much energy does pure fat oxidation require129 ATP
If I run at a ܄ሶ O2 of 2.0 L/min, how many calories will I burn in 30 minutes?300 kcal. because each litre of oxygen consumed makes 5kcal. 5X2 =10 . 10x 30 mins =300
Indirect calorimetry: limitation • CO2 production in cells may differ from CO2 exhalation (for example, hyperventilation) • RER does not take into account protein oxidation (protein may contribute up to 5% of total energy expended  RER is sometimes referred to as “nonprotein RER”) • Gluconeogenesis (catabolism of amino acids and fats in the liver) produces RER < 0.70 • RER > 1.0: Anaerobic metabolism, hyperventilation  Energy expenditure calculations only valid for RER values between 0.7 and 1.0

Section 2

What is basal metabolic rate (BMR)rate of energy expenditure at rest.
Under what conditions can you measure BMR– In supine position – Thermoneutral environment – After 8 h sleep and 12 h fasting
What does basal metabolic rate showthe minimum energy requirement for living.
What is BMR effected by – Related to fat-free mass, therefore women have lower BMR than men of a similar body mass – Also affected by body surface area, age, stress, hormones, body temperature
What affect does ageing have on basal metabolic rate 2-3% decrease/decade. – Decrease in fat free mass – Increase in body fat – Depression of metabolic activity of lean tissue
What is resting metabolic rateenergy expenditure at rest. – Less stringent rules than for basal metabolic rate – More applicable in many laboratory settings.
At what exercise intensity do i oxidise as much fat as possible (Romijn)65% V02 max.
At what exercise intensity do i oxidise as many plasma FFA as possible (Romijn)85% V02 max
Describe Fat and carbohydrate (CHO) oxidation during incremental cycling (male triathletes, VO2max= 59+5 mL/kg/min. Gonzalez-haro. Page 3, slide 16.
Describe Fatmax and trainability: Untrained vs trained women (܄ሶ O2max = 42 ± 2 and 54 ± 1 mL/kg/min)Fat oxidation, moderate intensityUntrained 0.31 +- 0.01. Trained: 0.38 +- 0.04. Fat oxidation at high intensity; Untrained 0.20+.0.02. Trained 0.27+- 0.04.