Chapters 2 and 8:

What are the three macronutrients that fuel the body?

Carbohydrates, Fat, Protein

What are the three forms of carbohydrates?

Monosaccharides, disaccharides, polysaccharides

What is the storage form of CHO in animals?

Glycogen

Where is glycogen stored in the body?

Liver and Muscles

What is the primary fuel at rest and during low intensity exercise?

Fat

What is the process of breaking down substrate into molecules?

Catabolic reaction

Does aerobic metabolism require oxygen?

Yes

Does anaerobic metabolism require oxygen?

No

What is the most important energy molecule in cells?

Adenosine Triphosphate (ATP)

What is PCr composed of?

Creatine and an inorganic phosphate.

What is the energy source for activities requiring a lot of energy per second, such as sprinting or lifting heavy weights?

ATP-PC system

How long can the ATP-PC system provide energy?

For a short time, around 5-6 seconds for a sprint and 20-30 seconds for a run/jog

At what exercise intensity does lactate begin to accumulate?

Lactate threshold

What is the process of converting lactate back to glucose in the liver?

Cori Cycle

What is the common point where all fuels meet at the start of aerobic ATP production?

Acetyl-CoA

What is the process of cleaving fatty acids?

Beta Oxidation

What is another name for the Krebs Cycle?

Citric Acid Cycle (TCA cycle)

What percentage of ATP is derived from CHO and fat at rest?

33% from CHO and 66% from fat

At maximal exercise intensity, what percentage of ATP comes from carbohydrates?

100%

During low-intensity, long-duration activity, what is the gradual shift in metabolism?

Carbohydrate to fat metabolism

What is VO2?

The volume of oxygen consumed

What does oxygen deficit represent?

The difference between total O2 consumed during exercise and the total O2 that would have been consumed had VO2 reached a steady state immediately

What is another term for oxygen debt?

Excess postexercise oxygen consumption (EPOC)

What type of recovery decreases blood lactate faster?

Active recovery

What does indirect calorimetry use to assess energy expenditure?

Measurements of VO2 and VCO2

What does RQ stand for?

Respiratory quotient

What is the RQ for carbohydrates?

1.0

What is the RQ for fat?

0.70

Why can RER be measured to be >1.0 during high intensity exercise?

Due to excess CO2 not produced from substrate breakdown

What is RMR?

Resting Metabolic Rate; the minimal amount of energy required to sustain the body's vital functions

What does BMR stand for?

Basal Metabolic Rate

What does MET stand for?

Metabolic equivalents

What is the preferred energy source for aerobic activity?

Carbohydrates

Why are carbohydrates the preferred energy source for aerobic activity?

They convert to ATP twice as fast as protein or fat, allowing for a faster sustainable pace. They produce 6% more ATP per unit of O2 consumed than lipids, making them more efficient for O2 use.

What percentage of total caloric intake should be comprised of carbohydrates for physically active individuals?

At least 50%

What is the goal of carbohydrate loading?

To increase muscle and liver glycogen stores

What kind of impact does CHO ingestion before exercise have on fuel use?

Increases CHO oxidation and decreases fat oxidation

Ingesting CHO more than 4 hours before exercise can increase what?

Muscle glycogen stores

What does a high insulin response lead to?

Large increase in glucose uptake (transient hypoglycemia), decrease in fat breakdown (lipolysis), increase in CHO oxidation (decrease in fat oxidation)

What is glycemic index?

A value representing how high a given meal increases blood glucose concentration

What are carbohydrate and electrolyte sports drinks intended to do?

○ Provide exogenous glucose to spare muscle glycogen34

○ Replace electrolytes and water lost in sweat

What is the goal of CHO ingestion after exercise?

To increase muscle glycogen content

What can a high protein diet lead to?

The development of ketone bodies due to low CHO intake

When is the best time to ingest protein for resistance training?

Before exercise, although after is also good because it is the period of muscle repair

What is the aim of protein intake for endurance training?

To restore glycogen, maintain FFM, and prevent muscle damage (soreness)

When is it generally better to take CHO + PRO for endurance training?

After exercise to avoid an insulin spike during exercise

What is the Atwater factor for triglycerides?

9 kcal/g

List three of the four sources of substrate location used in aerobic metabolism

Muscle Glycogen: The storage form of glucose in skeletal muscle. Muscle glycogen is a readily available source of energy for muscle contraction during high-intensity exercise.

Plasma Glucose: Glucose circulating in the bloodstream. Derived from the breakdown of liver glycogen or dietary intake, it is a primary energy source for low-intensity exercise and the brain.

Plasma FFA: Free fatty acids circulating in the bloodstream. serve as a major fuel source during rest and low-intensity exercise.

Muscle Triglyceride: Triglycerides stored within muscle cells. Muscle triglycerides, along with plasma FFAs, contribute to fat oxidation during exercise, particularly at lower intensities.

What are the physiological factors contributing to excess post oxygen consumption?

• Restoration of ATP and PCr: After exercise, the body needs to replenish its stores of ATP and PCr. This process requires oxygen and contributes to the elevated oxygen consumption observed during recovery.

• Lactate Metabolism: During intense exercise, lactate can accumulate in the muscles. EPOC supports the removal of lactate through oxidation in various tissues or conversion back to glucose in the liver (Cori cycle).

• Elevated Body Temperature: Exercise increases body temperature, which elevates the metabolic rate. EPOC helps to restore body temperature to its pre-exercise level.

• Hormonal Effects: Hormones like epinephrine and norepinephrine, released during exercise, can persist after the activity ceases, contributing to the increased metabolic rate and oxygen consumption seen in EPOC.

• Respiratory and Cardiovascular Adjustments: Ventilation and heart rate remain elevated after exercise to support oxygen delivery and carbon dioxide removal, contributing to EPOC.

• Resaturation of Oxygen-Carrying Molecules: Myoglobin in muscle tissue and hemoglobin in red blood cells need to be re-oxygenated after exercise, contributing to EPOC.

Specifically under anaerobic condition why is pyruvate converted to lactic acid at the end of glycolysis?

When NADH can not transport electrons (H+) to the electron transport chain, pyruvate takes H with NADH and is converted to lactic acid to regenerate NAD+, allowing glycolysis to continue.