Basal and Resting Metabolic Rate
34 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Why is it necessary to know both the RER and the amount of oxygen consumed to accurately estimate energy expenditure?

  • Because the caloric equivalent for oxygen is constant regardless of the nutrient oxidized.
  • Because oxygen consumption alone determines energy expenditure.
  • Because the RER only accounts for carbohydrate and protein oxidation.
  • Because the caloric equivalent for oxygen varies depending on the nutrient being oxidized. (correct)

Assuming protein contribution is negligible, what does an RER of 0.85 indicate about the fuel being used for energy production?

  • Primarily carbohydrate is being utilized.
  • An equal mix of carbohydrate, fat, and protein is being utilized.
  • Primarily fat is being utilized.
  • A mix of carbohydrate and fat is being oxidized. (correct)

Why is the protein contribution usually excluded from RER calculations in typical exercise physiology settings?

  • Protein oxidation does not produce CO~2~.
  • Measuring protein oxidation requires complex urine analysis and its energy contribution is relatively small. (correct)
  • The RER for protein is equal to 1.0.
  • Protein's contribution to energy production is high.

If a person with a mixed carbohydrate and fat diet has an RER of 0.85, approximately how many kilocalories are produced for every liter of oxygen consumed?

<p>4.86 kcal (D)</p> Signup and view all the answers

A researcher measures a subject's oxygen consumption and RER during a resting metabolic rate (RMR) test. Why is it essential to have both values for each minute of the measurement?

<p>To accurately determine the kilocalories produced per minute, accounting for the mix of carbohydrate and fat being oxidized. (A)</p> Signup and view all the answers

An individual with a desk job who engages in light exercise twice a week wants to estimate their Total Daily Energy Expenditure (TDEE). Which activity factor (AF) from the provided chart should they use to multiply their Resting Metabolic Rate (RMR)?

<p>1.375 (C)</p> Signup and view all the answers

A construction worker engages in heavy lifting and physical labor daily, and also participates in hard sports 6 days a week. Which activity factor should they use to estimate their TDEE?

<p>1.9 (C)</p> Signup and view all the answers

A 30-year-old woman who is 165 cm tall and weighs 68 kg leads a moderately active lifestyle. Using the Harris-Benedict equation, which calculation is needed to determine her RMR?

<p>$(9.563 \times 68) + (1.850 \times 165) - (4.676 \times 30) + 655.096$ (D)</p> Signup and view all the answers

If an individual calculates their TDEE to be 2500 kcal to maintain their current weight, what adjustments should they make to their daily caloric intake to lose weight?

<p>Consume fewer than 2500 kcal. (A)</p> Signup and view all the answers

A moderately active 45-year-old male, standing 180 cm tall and weighing 85 kg, uses the Harris-Benedict equation to estimate his RMR. To determine his TDEE for weight maintenance, what additional step must he take after calculating his RMR?

<p>Multiply the RMR by the appropriate Activity Factor. (C)</p> Signup and view all the answers

What are the three critical components directly measured by metabolic carts?

<p>Oxygen percentage, carbon dioxide percentage, and breath volume. (A)</p> Signup and view all the answers

Why is it important to measure local barometric pressure and ambient temperature when using a metabolic cart?

<p>They affect gas volume measurements. (A)</p> Signup and view all the answers

For best results, how often should data be averaged when using a metabolic cart?

<p>Every minute. (A)</p> Signup and view all the answers

Which of the following is a primary reason for using RMR prediction equations instead of direct assessment?

<p>Direct assessment can be cumbersome, costly, and requires trained technicians. (D)</p> Signup and view all the answers

What is the most important factor in determining the validity of an RMR prediction equation?

<p>The population in which it was developed. (B)</p> Signup and view all the answers

Which type of equation will outperform a body composition-based equation if used in the right population?

<p>A body weight-based equation. (A)</p> Signup and view all the answers

What is the purpose of applying an activity factor (AF) after estimating RMR?

<p>To adjust RMR for the individual's average daily activity level. (C)</p> Signup and view all the answers

How should an individual's activity level be considered when applying an activity factor (AF)?

<p>AF should reflect their typical or average daily activity. (A)</p> Signup and view all the answers

A researcher is studying energy expenditure in a group of generally active individuals. Which equation, incorporating body mass (BM), height (H), and age, is most appropriate according to the content provided?

<p>Ten Haaf and Weijs: 0.239[(49.94 × BM) + (2459.053 × H) -- (34.014 × age) + (799.257 × sex) + 122.502] (D)</p> Signup and view all the answers

Which of the following best describes the relationship between Basal Metabolic Rate (BMR) and Resting Metabolic Rate (RMR)?

<p>BMR is the minimum energy required under very strict conditions, while RMR is measured under less restrictive conditions. (D)</p> Signup and view all the answers

A researcher is preparing to measure a subject's RMR. Which of the following pre-test conditions is NOT required, according to the guidelines?

<p>Completing a light exercise session 2 hours before the test to stimulate metabolic activity. (A)</p> Signup and view all the answers

How would you modify the Mifflin-St. Jeor equation for a female subject when calculating resting energy expenditure?

<p>Use 0 for the sex variable. (D)</p> Signup and view all the answers

Indirect calorimetry estimates RMR by measuring:

<p>Oxygen consumption and carbon dioxide production. (A)</p> Signup and view all the answers

Why is the respiratory exchange ratio (RER) useful in metabolic studies?

<p>It provides insight into the type of fuel being oxidized. (C)</p> Signup and view all the answers

Under what condition are the respiratory quotient (RQ) and respiratory exchange ratio (RER) expected to be most similar?

<p>At steady state. (A)</p> Signup and view all the answers

Using the Weir equation, which variable has the greatest impact on RMR?

<p>Volume of oxygen consumed (VO<del>2</del>). (C)</p> Signup and view all the answers

A subject's expired breath is analyzed, and it's found that the concentration of oxygen has decreased compared to atmospheric air. What does this indicate?

<p>The subject has consumed oxygen during metabolic processes. (B)</p> Signup and view all the answers

Which equation is designed specifically for calculating resting metabolic rate in subjects with obesity?

<p>Owen equation (C)</p> Signup and view all the answers

What is the significance of using Fat-Free Mass (FFM) in predictive equations for resting metabolic rate?

<p>FFM is a more stable predictor of energy expenditure than total body weight. (D)</p> Signup and view all the answers

Why is it important to conduct RMR assessments in a dark room with no distractions?

<p>To promote relaxation and minimize unnecessary energy expenditure. (A)</p> Signup and view all the answers

According to the provided text, which component makes up the smallest percentage of TDEE?

<p>Thermic Effect of Feeding (TEF) (B)</p> Signup and view all the answers

If a person's RER is consistently around 0.7, what does this suggest about their primary fuel source?

<p>Primarily oxidizing fats (A)</p> Signup and view all the answers

A researcher measures VO2 at 2 L/min and VCO2 at 1.6 L/min. What is the RER, and what does it suggest about the fuel utilization?

<p>RER is 0.8, suggesting mixed fuel oxidation. (A)</p> Signup and view all the answers

A researcher finds it difficult for subjects to adhere to overnight stays in the metabolic lab when measuring BMR. What is a more practical alternative mentioned in the text?

<p>Measuring RMR instead of BMR. (C)</p> Signup and view all the answers

Flashcards

Resting Metabolic Rate (RMR)

The energy expenditure at rest in a neutral environment.

Activity Factor (AF)

A numerical factor representing a person's typical daily activity level.

TDEE

Total Daily Energy Expenditure: estimate of calories burned in a day.

Sedentary Activity Factor

desk job and little to no exercise (multiply by 1.2)

Signup and view all the flashcards

Extremely Active Factor

hard daily exercise/sports and physical job or training (multiply by 1.9)

Signup and view all the flashcards

Respiratory Exchange Ratio (RER)

Ratio of CO2 produced to O2 consumed; indicates substrate utilization.

Signup and view all the flashcards

RER for Carbohydrate

1.0, indicating carbohydrate is the primary fuel source.

Signup and view all the flashcards

RER for Fat

0.70, indicating fat is the primary fuel source.

Signup and view all the flashcards

Typical Resting RER

Approximately 0.85 in a mixed diet at rest.

Signup and view all the flashcards

Kcal per Liter O2 (RER = 0.85)

Approximately 4.86 kcal are produced per liter of oxygen consumed.

Signup and view all the flashcards

Metabolic Cart

Measures the percentage of oxygen and carbon dioxide in breath, and breath volume.

Signup and view all the flashcards

Barometric Pressure & Ambient Temperature

Local pressure and temperature affect gas volume measurement.

Signup and view all the flashcards

Mixing Chamber

Averages gas measurements over a set time.

Signup and view all the flashcards

RMR Prediction Equations

Estimates RMR using height, weight, age, sex, and sometimes body composition.

Signup and view all the flashcards

Population (for RMR equations)

The group of people that the equation was created from.

Signup and view all the flashcards

Average Activity Level

How active a person typically is during their daily life.

Signup and view all the flashcards

RMR

Resting Metabolic Rate. The rate of energy expenditure at rest.

Signup and view all the flashcards

Mifflin-St Jeor Equation

An equation to estimate Resting Metabolic Rate (RMR).

Signup and view all the flashcards

VO2

VO2 refers to the volume of oxygen consumed by the body, reflecting energy expenditure.

Signup and view all the flashcards

VCO2

VCO2 refers to the volume of carbon dioxide produced by the body.

Signup and view all the flashcards

Respiratory Quotient (RQ)

Macronutrient oxidized at the cellular level during steady state.

Signup and view all the flashcards

VCO2/VO2 Ratio

The volume of carbon dioxide produced relative to the volume of oxygen consumed.

Signup and view all the flashcards

RQ/RER Formula

RQ/RER = VCO2 / VO2

Signup and view all the flashcards

FFM

Fat Free Mass

Signup and view all the flashcards

Basal Metabolic Rate (BMR)

The minimum energy needed to sustain vital body functions while awake, measured in kcal/day.

Signup and view all the flashcards

Total Daily Energy Expenditure (TDEE)

Total energy expenditure in a day, consisting of BMR, thermic effect of feeding (TEF), and activity thermogenesis (AT).

Signup and view all the flashcards

Activity Thermogenesis (AT)

Energy burned through physical activity, including both exercise and non-exercise activities.

Signup and view all the flashcards

Exercise Activity Thermogenesis (EAT)

Energy burned during structured exercise.

Signup and view all the flashcards

Nonexercise Activity Thermogenesis (NEAT)

Energy burned during daily activities that aren't structured exercise (e.g., walking, fidgeting).

Signup and view all the flashcards

Indirect Calorimetry

A technique that measures oxygen consumption (VO2) and carbon dioxide production (VCO2) to estimate RMR.

Signup and view all the flashcards

Weir Equation for RMR

RMR = 1.44 × [(VO2 × 3.9) + (VCO2 × 1.1)]

Signup and view all the flashcards

Study Notes

  • Basal metabolic rate (BMR) is the minimum energy needed to sustain vital functions while awake, measured in kcal/day.
  • BMR constitutes the largest portion of total daily energy expenditure (TDEE).
  • TDEE comprises BMR (60-75%), the thermic effect of feeding (TEF, 10%), and activity thermogenesis (AT, 15-30%).
  • Activity thermogenesis includes exercise activity thermogenesis (EAT) and nonexercise activity thermogenesis (NEAT).
  • True BMR requires overnight stays in a metabolic lab due to strict sleep and fasting requirements.
  • Resting metabolic rate (RMR) is measured instead, requiring resting and fasting, but not overnight stays.

Guidelines for RMR Assessment

  • Fast from all calorie-containing food and beverages for at least 8 hours.
  • Rest in a dark, distraction-free room for 30 minutes before the test.
  • Abstain from exercise for at least 24 hours.
  • Avoid caffeine or other stimulants for at least 12 hours prior to the test.
  • RMR can be assessed anytime if the above conditions are met, but mornings are preferred for comfort and overnight fasting.
  • RMR assessed via indirect calorimetry, using metabolic carts to measure carbon dioxide (VCO2) production and oxygen (VO2) consumption.
  • Atmospheric composition: 20.93% oxygen, 0.03% carbon dioxide, 79.04% nitrogen.
  • Expired breath differs as oxygen decreases, carbon dioxide increases, but nitrogen remains unchanged.

Weir Equation for Estimating RMR

  • RMR = 1.44 × [(VO2 × 3.9) + (VCO2 × 1.1)]
  • Oxygen consumption and carbon dioxide production reflect the fractions of these gases in air and expired breath, as well as air volume per breath.
  • Metabolic carts measure percentages of oxygen and carbon dioxide in expired breath and breath volume.
  • Gas volume is affected by temperature and pressure, making local barometric pressure and ambient temperature important measurements.
  • Some metabolic carts measure expired gases, ventilation, temperature, and pressure per breath; others use a mixing chamber for averages.
  • One-minute averages are recommended for best data.

Estimating Resting Metabolic Rate

  • Directly assessing RMR can be difficult, costly (>$60,000), and require trained technicians.
  • Prediction equations are commonly used in field settings.
  • Prediction equations use metrics like height, weight, body composition, age, and sex.
  • Equation validity depends on the population it was developed for.
  • Body weight-based equations can outperform body composition-based ones if used in the correct population.
  • RMR is converted to TDEE using an activity factor (AF).
  • AF estimates a person's average daily activity level
  • Sedentary (desk job, little exercise): multiply by 1.2
  • Lightly Active (light exercise/sports 1–3 days/week): multiply by 1.375
  • Moderately Active (moderate exercise/sports 3–5 days/week): multiply by 1.55
  • Very Active (hard exercise/sports 6–7 days/week): multiply by 1.725
  • Extremely Active (hard daily exercise/sports and physical job or training): multiply by 1.9
  • TDEE = RMR × AF estimates the kilocalories needed to maintain weight.
  • Consume below this number for weight loss and above it for weight gain.

Respiratory Exchange Ratio and Respiratory Quotient

  • Respiratory quotient (RQ) or respiratory exchange ratio (RER) indicates the type of fuel being used.
  • RQ and RER differ only in measurement location: cellular level and expired gases, respectively; this lab refers to RER.
  • RER is calculated as VCO2 / VO2
  • Ratios measure carbon dioxide produced relative to oxygen consumed.
  • Carbohydrate, fat, and protein require different oxygen amounts for oxidation.
  • Caloric equivalent for oxygen varies depending on the nutrient oxidized, requiring RER knowledge.
  • Kilocalories produced per liter of oxygen consumed depend on the utilized substrate or RER.
  • RER values: 1.0 for carbohydrate, 0.70 for fat, 0.82 for protein.
  • Protein contribution to energy production is low (generally less than 5%).
  • RER is generally considered to be nonprotein RER due to the complexity of analysis
  • Kilocalories produced per liter of oxygen consumed depends on whether fuel mix of carbohydrate and fat .
  • RER value of 0.85 at rest with a mixed diet is about 4.86 kcal produced per 1 L of oxygen consumed.
  • Researchers must measure oxygen consumption and RER value to determine kilocalories produced per minute.
  • Carbohydrate's RER is 1.0, while fat's RER is 0.7
  • Carb oxidation: C6H12O6+6 O2 → 6 CO2 + 6 H2O + 38 АТР
  • Fat Oxidation: C16H32O2 + 23 O2 → 16 CO2 + 16 H2O + 129 АТР

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Resting Metabolic Rate Lab - Exercise Physiology PDF

Description

Explore basal metabolic rate (BMR) and resting metabolic rate (RMR), key components of total daily energy expenditure (TDEE). Understand the guidelines for accurate RMR assessment, including fasting and rest requirements. Learn how these measurements differ and their significance in energy expenditure.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser