Kinesiology 3339A/B Lecture Notes - Lecture 9: Resting Metabolic Rate, Anaerobic Glycolysis, Oxidative Phosphorylation
19 Oct 2016
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Lecture 9!
Kinesiology 3339: Exercise Nutrition !
Basic Nutrition Part 4
Catabolic Processes
•Part of metabolism that take stored energy and uses it for exercise
•The pathway that you use is dependent on the ATP needed for the activity, which is dependent on how
intense the activity is
-Phosphagen stores: greatest rate but stores limited to a few seconds of ATP
•Anaerobic glycolysis: next greatest rate but limited to 30 seconds to a few minutes maximum by lactic
acid accumulation
-Lactic acid accumulated and shuts down process by inhibiting enzymes earlier in the pathway
•Oxidative phosphorylation: very long duration by slowest rate; limited by oxygen delivery (VO2 max)
and fuel supply (CHO, fat)
-This process is influences by ability to provide substate in the form of CHO and fat
-Can run out of CHO, can still get energy from this pathway but rely on utilization of fat, and
fat requires even more oxygen
-If exercising at max, and need more oxygen, cannot use fat
-If you want to use fat for fuel supply, cannot exercise as hard, need to slow down
-This is known as glycogen depletion = cannot exercise as hard
Metabolism
•Metabolism: all physical and chemical transformations in the body (anabolism + catabolism)
-Anabolic: e.g., synthesis (build-up) during growth or training (overload leads to increased
skeletal muscle mass and strength with strength training or increased muscle oxidative
enzymes with endurance training)
-Catabolic e.g., formation of ATP from phosphagen
-Or breakdown of glycogen to glucose to lactic acid and ATP (anaerobic glycolysis)
-Or glycogen, fat, and/or protein to CHO2, H2O and ATP (oxidative phosphorylation)
-The energy (ATP) from catabolic processes is used to fuel anabolism
-With growth, anabolism exceeds catabolism
-With wasting, catabolism exceeds anabolism
-Nutrient (food) intake critical to maximize growth and/or maximize wasting
-Metabolic rate: is measure of how rapidly the body is using its stored energy
-When expressed for one day it is called Total Daily Energy Expenditure (TDEE)
-Determined by 3 potential components:
-1. Resting energy expenditure: rate that you are using energy when doing nothing
-2. Food intake: chewing, absorbing and digesting food requires energy, but still have
more energy than expenditure
-3. Physical activity: if you are exercising hard and a lot, can be >50% energy
expenditure in a day. But for most Canadians this does not apply
-In most common diets - emphasize protein and decrease consumption of CHO and fat because
protein stimulates metabolism
-Can increase expenditure of energy or decrease energy expenditure by controlling physical
activity
Metabolism - Resting Expenditure
•Resting expenditure (resting metabolic rate RMR or resting energy expenditure REE
•basal functioning (BMR) + small increment due to previous physical activity
•Typically RMR is measured (Exceeds BMR by <10%)
•RMR is about 1 kcal per kg body mass per hour
•Rate is related to:
•Muscle mass (generally people who have higher muscle have righter resting metabolic rate)
•Age, gender, fitness, weight loss, low energy diets (hormones), caffeine, smoking
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Catabolic processes: part of metabolism that take stored energy and uses it for exercise, the pathway that you use is dependent on the atp needed for the activity, which is dependent on how intense the activity is. Phosphagen stores: greatest rate but stores limited to a few seconds of atp: anaerobic glycolysis: next greatest rate but limited to 30 seconds to a few minutes maximum by lactic acid accumulation. Lactic acid accumulated and shuts down process by inhibiting enzymes earlier in the pathway: oxidative phosphorylation: very long duration by slowest rate; limited by oxygen delivery (vo2 max) and fuel supply (cho, fat) This process is influences by ability to provide substate in the form of cho and fat. Can run out of cho, can still get energy from this pathway but rely on utilization of fat, and fat requires even more oxygen. If exercising at max, and need more oxygen, cannot use fat.
