Exercise Metabolism Flashcards
Adenosine Triphosphate (ATP)
The main form of energy in the human body.
Made of:
Adenine (a nitrogenous base)
Ribose (a sugar molecule)
Phosphate groups (3 linked w/ High Energy bonds)
Bioenergetics
The study of biochemical reactions that manage energy in the body.
Metabolism
All chemical reactions that occur in the body to maintain itself.
Exercise Metabolism
The relationship of bioenergetics to physiological changes and demands from exercise.
Energy Metabolism: flowchart
Intake: Chemical energy in the form of macronutrients, Carbs and Fats.
Conversion: Carbs & Fats into ATP
Metabolic process to use energy
Express: Chemical waste in the form of Co2, water & heat.
First law of thermodynamics
Energy cannot be created or destroyed, only recycled or converted from one form to another, known as ENERGY BALANCE.
This is the reason why energy taken into the body is stored as excess mass when it is not used to perform activity.
Substrates
Intermediate forms of nutrients used in metabolism to create ATP.
Protein’s amino acid chains
Carbs
Fats
The label “essential nutrient”
Substrates that cannot be created internally and must be consumed in the diet.
Glucose vs. Glycogen
The simplest form of Carb used by the body to make energy.
Derived from Carbs, but can also be made internally via gluconeogenisis by breaking down protein’s amino acids, or Fats.
Glucose is used to make ATP or stored in liver & muscle cells as Glycogen for later use.
Glucose is used for brain function & high energy exercise, but Fats primarily fuel the body at rest.
Glucose vs Fat for energy production
Glucose is used when the body needs a quick way to produce energy. It can be used faster than Fat because it can be metabolized anaerobically.
Fat must be converted to ATP in the presence of Oxygen.
Ventilatory Threshold 1 (vt1)
The point of exercise intensity where the body is using a 50:50% mix of Carbs & Fats to fuel the body.
Ventilatory Threshold 2 (vt2)
The point at which exercise intensity is so high, that only glucose can meet the body’s energy demands.
Glycolysis produces more co2 than fat oxidation, so not only does inhaling increase, but the need to rapidly exhale co2 also increases, making talking very hard.
Fat & Triglycerides
A macronutrient that is an important energy source during rest & sub-v1 exercise.
Its substrate form is Triglyceride, which is known as Free Fatty Acid when it is in the bloodstream.
Triglycerides are consumed in the diet & are made by the liver.
High Carb intake causes the liver to convert excess calories into Triglycerides.
They are stored in fat cells until needed. Then they are released as Free Fatty Acids for energy production.
Protein
Macronutrient made up of long chains of amino acids linked by peptide bonds that are the building blocks of body tissue.
20 amino acids are used by the body & 9 are essential
Essential vs. Non-essential Aminos
Essentials must be consumed in the diet, since they can’t be synthesized in the body. There are 9:
Non-essentials can be synthesized in the body from consumed Carbs & Fats.
Negative Energy Balance
Insufficient Carb or Fat substrates availability leads to the recruitment of Protein’s amino acids for energy production.
These aminos are derived from newly consumed Protein or the breakdown of muscle tissues.
Uses processes of gluconeogenesis or ketogenesis.
Ketogenesis
The formation of Ketone bodies (3 molecules: acetone, acetoacetic acid & beta-hydroxybutyric acid Bhb) produced by the liver from NON-FAT sources, like Protein’s amino acids or by-products of fatty acid breakdown.
Used for quick fuel, as the can be ANAEROBICALLY metabolized similar to glucose.
Ketosis
When the body runs low on glucose or glycogen stores, the liver produces Ketone bodies (3 molecules of acetone, acetoacetic acid & beta-hydroxybutyric acid Bhb)
The Ketone bodies cannot be stored & must be used immediately. Together w/ gluconeogenic glucose, they resolve glucose/glycogen deficiency.
The 3 Ketone Bodies
Acetone
Acetoacetic Acid
Beta-hydroxybutyric Acid, (Bhb)
Conditions for Ketosis
Very low overall calorie consumption
Low-carb, or Ketogenic Diets
Consuming Exogenous Ketones
Lack of insulin or insulin resistance
Nutritional Ketosis vs Ketoacidosis
Dietary and supplementary means to increase ketone levels between 0.5-1.5 mmol/L
Levels of Ketones, which are acidic, are too high, causing metabolic acidosis, as seen in type 1 diabetes or severe insulin resistance.
ADP
Adenosine diphosphate
When ATP is used for mechanical work, one of the 3 HIGH ENERGY phosphate bonds is broken, resulting in ADP & a free phosphate group.
Will convert back to ATP when enough food derived or bodily stored substrates become available.