Kin 310: Lab 1 - Energy Expenditure

Indirect calorimetry

A method to estimate energy expenditure by measuring gas exchange (O2 uptake and CO2 production) using devices like Douglas bags and a metabolic cart.

Douglas bag

A flexible bag used to collect expired air for later analysis of O2 and CO2.

VO2

Volume of oxygen consumed per minute.

VO2max

Maximum rate of oxygen consumption during progressive exercise; an index of aerobic fitness.

STPD

Standard Temperature, Pressure, Dry; standard conditions used to standardize gas volumes for comparison.

Pneumotach

A flow sensor inside the respiratory apparatus that measures flow rate and respiratory rate to compute expired air volume (VE).

VE (minute ventilation)

Total volume of air expired per minute.

FIO2

Fraction of inspired oxygen in the air the participant breathes.

FEO2

Fraction of expired oxygen in the expired air.

FECO2

Fraction of expired carbon dioxide in the expired air.

FI_CO2

Fraction of inspired CO2 (usually near zero in room air).

VO2 equation

VO2 = VE × (FIO2 − FEO2); oxygen consumption is the product of ventilation and the difference between inspired and expired O2 fractions.

MET

Metabolic equivalent; 1 MET = 3.5 mL·kg⁻¹·min⁻¹, roughly resting energy expenditure.

Borg scale (RPE 6–20)

A subjective rating of perceived exertion used to gauge exercise intensity.

Lt LabStation

Software used to collect and analyze ECG and respiratory data during the lab.

ECG/EKG

Electrocardiography; method to measure heart rate.

Three-way tap

Valve that directs expired air either into a Douglas bag or back to the room; used to control sample collection.

Nonrebreathing valve

Mouthpiece system allowing inhaled room air while ensuring exhaled air passes through the sampling line.

Resting VO2

VO2 measured at rest during a seated rest period (e.g., 3 minutes) to establish baseline values.

VO2max testing protocol

Graded treadmill test with stages of increasing intensity to voluntary exhaustion, measuring VO2, HR, and RPE.

Fox max HR equation

Age-predicted maximum heart rate: HRmax ≈ 220 − age.

Tanaka max HR equation

Age-predicted maximum heart rate: HRmax ≈ 208 − 0.7×age.

Absolute VO2

Oxygen consumption expressed in liters per minute (L/min).

Relative VO2

Oxygen consumption expressed in mL per kg body weight per minute (mL·kg⁻¹·min⁻¹); conversion from L/min: multiply by 1000 and divide by mass (kg).

1 MET

Equivalent to 3.5 mL·kg⁻¹·min⁻¹; the resting oxygen consumption.

Disinfecting protocol (OPA/28)

Procedure to disinfect lab equipment after use using OPA/28 solution and gloves.

System International (SI) units

Metric system used to report scientific data in exercise science (e.g., kg, m, s, N, J, W, m/s).

Kilogram (kg)

SI unit of mass.

Meter (m)

SI unit of distance.

Second (s)

SI unit of time.

Newton (N)

SI unit of force.

Joule (J)

SI unit of work and energy.

Watt (W)

SI unit of power.

Meters per second (m/s)

SI unit of velocity.

1 inch = 2.54 cm

Conversion factor from inches to centimeters.

100 cm = 1 m

Conversion factor from centimeters to meters.

Kilogram to pounds (1 kg = 2.2 lbs)

Approximate conversion used in this course (2.2 is used instead of 2.20462).

1 L O2 = 5 kcal

Conversion linking oxygen consumption to energy expenditure.

1 MET = 3.5 ml/kg/min

Metabolic equivalent; oxygen uptake value used to express energy expenditure.

HRmax

Maximum heart rate, the upper limit of heart rate during max effort.

Fox equation

HRmax = 220 − age.

Tanaka equation

HRmax = 208 − (age × 0.7).

Body Mass Index (BMI)

BMI = kg / m^2; index of body composition.

BMI thresholds

BMI > 30 indicates obesity; BMI < 18.5 indicates underweight.

Fat-Free Mass (FFM)

Mass of all non-fat tissues; influences BMR.

Basal Metabolic Rate (BMR/RMR)

Energy used while at rest to maintain vital bodily functions; influenced by age, sex, and FFM.

Diet-Induced Thermogenesis (DIT)

Energy used to digest, absorb, and process food; some heat produced.

Total Energy Expenditure (TEE)

Total energy used daily, consisting of BMR, DIT, and physical activity.

Indirect calorimetry

Measuring energy expenditure via oxygen consumption and carbon dioxide production.

Expired ventilation (VE)

Volume of air expired; used in VO2 calculations.

VO2

Volume of oxygen consumed; VO2 = VE × (FIO2 − FEO2).

FIO2

Fraction of inspired oxygen in the air.

FEO2

Fraction of expired oxygen in the exhaled air.

Tidal Volume (VT)

Volume of air per breath.

Pneumotachometer

Device measuring air flow rate via a pressure difference across a mesh.

Bell spirometer

Old device using a floating bell to measure lung volume.

Douglas bag

Bag used to collect expired air for later analysis.

Metabolic cart

System with computer, mixing chamber, pneumotach, and a mouthpiece to measure VO2 and related variables.

Mixing chamber

Component that collects expired air before analysis.

Nose clip

Accessory worn to ensure all air exits through the mouth during testing.

Mouthpiece with one-way valve

Mouthpiece allowing inhalation from the room and exhalation into the cart.

Inspired oxygen concentration (~20.93%)

O2 content of inspired air in ambient conditions.

Douglas bag method

Traditional method of collecting expired air for gas analysis; largely replaced by metabolic carts.

VCO2

Volume of carbon dioxide produced; used with VO2 in metabolic measurements.