Assessment of Energy Expenditure Flashcards

Flashcards covering the components of energy expenditure, measurement techniques such as direct and indirect calorimetry, and metabolic estimation equations.

BMR

Basal Metabolic Rate, which accounts for $65-75\%$ of the components of energy expenditure and is primarily dictated by body mass.

DIT/TEF

Diet-Induced Thermogenesis or Thermic Effect of Food, representing approximately $10\%$ of total energy expenditure.

Physical Activity

A component of energy expenditure that accounts for $15-30\%$ of the total.

kJ calculation

The formula used to convert kilocalories to kilojoules is $\text{kcal} \times 4.2$.

MJ calculation

The formula used to convert kilocalories to megajoules is approximately $\text{kcal} / 239$.

Direct Calorimetry

An assessment method that measures energy expenditure through the body's heat production, often using a whole-body calorimeter.

Indirect Calorimetry

An assessment method that estimates energy expenditure by measuring oxygen uptake ($VO_2$) and carbon dioxide production ($VCO_2$).

Douglas Bag Technique

A specific technical method used within Indirect Calorimetry to assess metabolic rate.

Steady State Exercise

A condition in exercise physiology where oxygen uptake ($l/min$) plateauing over time allows for the estimation of energy expenditure.

Schofield Equation

A formula used to estimate an individual's BMR (in $kcal/day$ or $MJ$) based on age, height, and weight.

MET (Metabolic Equivalent)

A multiple used to represent intensity where $1\text{ MET} = \text{BMR}$; for example, $4.5\text{ METs}$ is the middle of the intensity range recommended by the UK Government.

Problems with Direct Calorimetry

Includes the inability to monitor rapid changes, interference from ergometer friction heat, potential delayed heat liberation from the body, and the inability to determine specific fuel utilization.

Temporal Considerations

The contrast between brief periods of exercise (e.g., $2-3$ hours a week) versus the much larger 'Movement Opportunity' during waking hours (approximately $112$ hours).