Ex. Phys. - Chapter 5: Energy Expenditure and Fatigue

What does direct calorimetry measure?

Heat.

What is the respiratory exchange ratio formula?

RER = VCO2/VO2

What does respiratory exchange ratio measure?

The rate of CO2 released and oxygen consumption (VO2).

In generally, the amount of oxygen needed to completely oxidize a molecule of carbohydrate or fat is proportional to the amount of what in that fuel?

Carbon.

During carbohydrate oxidation, approximately how many molecules of ATP are produced for each molecule of oxygen used?

6.3 molecules of ATP are produced for each molecule of oxygen used.

During palmate acid metabolism, how many ATP are produced?

129 ATP.

Arterial blood remains almost completely oxygen saturated at about what percentage?

About 98%+

What is the RER value at rest?

.78 - .80

What is the RER value for the oxidation of fat?

.70

What is the RER value to the oxidation of carbs?

1.00

What the metabolic rate?

The rate at which the body uses energy.

Knowing a peons's what allows us to calculate their caloric expenditure.

VO2

What is the standardized measure of energy expenditure at rest?

Basal Metabolic Rate.

The higher the fat free mass, are more or less calories expended?

More.

Explain VO2 drift...

A slow increase in VO2 during prolonged, sub maximal, constant power output exercise.

What is widely regarded as the best single measure of cardiorespiratory endurance or aerobic fitness?

VO2 max, otherwise known as maximal oxygen uptake.

Normal, active, but untrained 18 -22 years old college students have an average Vo2 max ranging in about what ml per kilogram of bodyweight per minute?

38 - 42/kg body weight/min.

After the age of 25 to 30 years olds who are inactive, the rate of VO2 max goes down how much percent a year?

1 percent/year.

What are among the most common methods for estimating anaerobic effort?

The examination of either the excess post oxygen consumption (EPOC) or the lactate threshold.

What is considerate a good indicator of an athlete's potential for endurance exercise?

The lactate threshold.

What is the lactate threshold?

The point at which blood lactate beings to substantially accumulate above resting concentrations during exercise if increased intensity.

Lactate threshold it typically expressed as a percentage of what?

VO2 max.

What factors contribute to fatigue?

Decreased rates of energy deliver, accumulation of metabolic by-products, failure of the muscle fiber's contractile mechanism, alterations in neural control of muscle contraction.

Fatigue coincides with what type of system depletion.

PCr depletion.

At about what milage to endurance runners typically report hitting the wall?

At about miles 18 to miles 22.

The sensation of "hitting the wall" can be attributed to what?

Muscle glycogen depletion.

The liver breaks down a lot of its stored what to provide a constant supply of blood what?

The liver breaks down a lot of its sorted glycogen to provide a constant supply of blood glucose.

As glycogen is depleted, exercising muscles rely more heavily on the metabolism of what?

FFAs.

When not cleared, the lactic acid dissociated, converting the lactate and causing an accumulation of what type of ions?

Hydrogen.

The accumulation of hydrogen ions causes muscle acidification resting in a condition known as what?

Acidosis.

What do bicarbonate buffers do?

They minimize the disputing influence of the Hydrogen ions.

During maxima, all-out exercise lasting more than 20 or 30 seconds, what do most researchers agree to be the major limiting fact causing fatigue.

Low muscle pH.