EXS 101 Chapter 8 (Measurement of Human Expenditures)

What defines the measurement of heat transfer?

Calorimetry

All of the body’s metabolic processes ultimately result in what?

Heat production

What represents a basic unit of heat measurement?

Calorie (kcal)

What are four calorimeter types?

Airflow calorimeter, Water flow calorimeter, Gradient layer calorimeter, and Storage calorimeter.

What measures energy expenditure via heat production with limited practical application to humans?

Direct Calorimetry

What is a human calorimeter?

Scientists in the 1890s developed techniques to assess human metabolic heat production.

What is an all energy-releasing reaction in humans that ultimately depends on oxygen use? Measuring someone’s breath can give an accurate estimate of energy expenditure.

Indirect Calorimetry

What is closed-circuit spirometry?

A simple method that directly measures O2 uptake but has limited practical applications. Cannot assess energy expenditure during dynamic movements.

What is open-circuit spirometry?

A simple and practical way to measure O2 uptake and CO2 production to infer energy expenditure. Subject inhales ambient air (20.93% O2, 0.03% CO2, 79.04% N2).

What are three indirect open-circuit calorimetry procedures?

Bag technique, Portable spirometry, and computerized instrumentation.

What is the Micro-Scholander technique for gas analysis?

This measures oxygen and carbon dioxide (0.5 mL sample)

What is the Haldane method technique for gas analysis?

This measures a larger air sample (100 mL)

What is the doubly labeled water technique?

Safe way to estimate total daily energy expenditure. The subject consumes water with a known concentration and then records every time they produce a bodily fluid. This has within 3-5% accuracy in comparison to laboratory measured energy expenditure.

What is a Respiratory Quotient?

The ratio of metabolic gas exchange. RQ = CO2 produced / O2 consumed

What is the RQ for carbohydrates?

1.00

What is the RQ for fats?

0.7

What is the RQ for protein?

0.82

What does nonprotein RQ mean?

The composition of the RQ composed of carbohydrates and fats.

What is the Respiratory Exchange Ratio (Same as RQ)?

RER = CO2 produced / O2 consume

What is an increase in CO2 compared to current metabolic demands (over breathing)?

Hyperventilation

What happens during intense exercise that produces a weaker carbonic acid, which degrades to CO2 and H2O with the lungs readily expelling CO2?

Buffering