Metabolic Rates

Overview:

Exercise physiology examines how physical activity influences the body’s cardiovascular system, endocrine system, and musculoskeletal system. Exercise tests are usually performed under constant or increasing workloads. Constant workloads are designed for subjects to reach a steady state of gas exchange, ventilation and heart rate, thereby investigating cardiopulmonary function under constant metabolic demand. Increasing work loads are used to reach exhaustion in the subject and determine a maximal level of oxygen consumption. 

 

 

 

Method:

Metabolic Measurements in Humans

For a typical exercise physiology study the following variables are recorded:

  • Inspired or expired air flow using a pneumotach (spirometer and flow head)
  • Expired CO2 and O2 concentrations from a Gas Mixing Chamber using a Gas Analyzer
  • Temperature of the expired air

The simultaneous measurement of respiratory gas concentrations and air flow permits the calculation of the following metabolic parameters:

  • VO2, the rate of oxygen consumption (L/min)
  • VCO2, the rate of carbon dioxide production (L/min)
  • RER, respiratory exchange ration (VCO2/VO2)
  • VE, the expired minute ventilation (L/min)

The Exercise Physiology System, together with a work load protocol such as a cycle ergometer or treadmill (increasing work load) or step and walking tests (constant work load), can be used for exercise physiology studies in humans. The system includes:

  • An 8 channel PowerLab data acquisition unit
  • Gas Analyzer for accurate O2 and CO2 measurements
  • Gas Mixing Chamber for mixing expired gases prior to sampling
  • Spirometer for differential pressure measurements of respiratory air flow
  • Thermistor Pod for measuring the temperature of expired gases and is necessary to correct for differences between expired and atmospheric conditions.
  • Single Channel Bio Amp for optional recordings of biopotentials such as ECG or EMG
  • Metabolic Module for LabChart (Win or Mac) software that provides online or offline calculation and display of VE, VO2, VCO2 and RER

Wireless Recording in Humans

The BioHarness Telemetry System together with LabChart software enables wireless recording and analysis of multiple human biopotentials with a single device. Designed for exercise physiology study, the BioHarness is constructed with patented Smart Fabric Sensor Technology integrated into a comfortable, unobtrusive belt-like garment and is worn around the chest by human subjects. Using the BioHarness Extension, signals such as ECG (live transmission only), breathing rate and depth, heart rate, skin temperature, posture, peak acceleration and activity can be acquired and analyzed in real-time. Offline analysis with LabChart is also possible using the BioHarness device in logging mode.

Also available for wireless recording in human subjects is the Wireless Heart Rate Kit which offers wireless connectivity between a chest strap and a PowerLab via a Polar Receiver Interface Cable. It is ideal for measuring heart rate during exercise and performing HRV studies using the HRV Module for LabChart in real-time or offline.

Metabolic Measurements in Animals

Metabolic function in animals can be measured using a custom configuration that includes the Spirometer and Gas Analyzer. For example, the unrestrained or restrained animal may be kept in a plethysmograph chamber and respiratory air flow and gas concentrations monitored.

Note: For more information on related topics please see:

  • Temperature application page for temperature measurements
  • Respiratory Gas Analysis application page for O2 and CO2 analysis in respiratory gasses
  • HRV application page for heart rate variability measurements

Software:

The LabChart Advantage:

(may require additional Modules and Extensions)

  • The Metabolic Module (Win or Mac) for LabChart calculates and displays ventilatory parameters such as VCO2, VO2, VE and RER online from measurements of %O2, %CO2 and air flow
  • The Spirometry Extension (Win or Mac) for LabChart calculates tidal volume, minute ventilation, PIF, PEF, respiratory rate, FVC, FEV1 and can construct flow-volume loops online or offline (also see Respiratory Airflow application pages)
  • Transfer data easily to word processing or spreadsheet programs for further analysis and publication-quality reports
  • Annotate data files with Comments about experimental conditions
  • Respiratory rate can be calculated using Cyclic Measurements (Win) or Computed Input/Cycle Variables (Mac)
  • The BioHarness Extension (Win) for LabChart together with the BioHarness hardware records and analyzes signals such as ECG (live transmission only), breathing rate and depth, heart rate, skin temperature, posture, peak acceleration and activity online or offline.

LabChart

LabChart software (for Windows and Macintosh) together with a PowerLab data acquisition system offers up to 32 channels of real-time data acquisition, data integrity, easy selection of hardware settings, powerful online and offline analysis, procedure automation, seamless extraction of experimental data and flexible display options. Additional acquisition and analysis functionality is provided with the use of specialized LabChart Extensions and LabChart Modules. Modules are available as part of LabChart Pro while Extensions are free for download from the website for existing LabChart users. 

Metabolic Module

The Metabolic Module for LabChart (Windows and Macintosh) in combination with ADInstruments hardware is ideal in the determination of cardiorespiratory function and exercise physiology measurements. Typical applications include:

  • Metabolic measurements
  • Respiratory gas analysis
  • Student exercise testing
  • Pulmonary function analysis
  • Anaerobic threshold
  • Biopotential measurements and spirometry

The Metabolic Module records CO2 and O2 concentrations sampled from a gas mixing chamber and interprets these values in real time to provide parameters such as: VCO2/min, VO2/min, VE/min and RER. The module also provides options for setting subject details, recording parameters and environmental conditions that includes:

  • Hardware preferences: Choice of appropriate hardware
  • Subject details: Name, Age, Weight, Height, Gender, ID number, Comments
  • Calibration preferences: Settings for automated first and second gas calibrations
  • General preferences: Averaging time (data logging) and recording time (duration of experiment) settings
  • Environment settings: Expired/inspired, atmospheric and air conditions 

Heart Rate Variability (HRV) Module

The HRV Module for LabChart (Windows and Macintosh) provides a comprehensive set of tools for the real-time or offline analysis and display of variation in heart rate during rest or exercise. The HRV Module can:

  • Detect and analyze R waves & RR interval variation in ECG
  • Include or exclude ectopic beats from analysis
  • Add R waves or remove short artifacts from analysis
  • Export data analysis parameters
    • NN Intervals, RR Intervals, Spectrum NN Intervals & Report
  • Display HRV Analysis Windows
    • Poincaré Plot, Tachogram & Spectrum
    • Period Histogram & Delta NN Histogram

 

Spirometry Extension

The Spirometry Extension for LabChart (Windows and Macintosh) provides:

  • Automated calibration of respiratory flow and volume recordings
  • Advanced analysis functions
  • Generation of flow-volume plots
  • Calculation of tidal volume and respiratory rate
  • Calculation of minute ventilation, peak inspiratory and expiratory flow

 

BioHarness Extension

The BioHarness™ Extension for LabChart (Windows) will only work with BioHarness ISM Modules and Receivers that have been sold and programmed by ADInstruments. A PowerLab data acquisition unit is not required to use the BioHarness with LabChart software.

Signals such as ECG (live transmission only), breathing rate and depth, heart rate, skin temperature, posture, peak acceleration and activity can be acquired and analyzed in real-time or offline.

GLP and 21 CFR Part 11

For those researchers working within a laboratory requiring GLP and 21 CFR Part 11 compliance the GLP Client and GLP Server are available for use with LabChart (Windows only) and PowerLab data acquisition systems. For more information, visit the Good Laboratory Practice application page or contact your nearest ADInstruments representative.

Hardware:

PowerLab Data Acquisition Systems

The PowerLab is a high-performance data acquisition unit capable of recording at speeds of up to 400,000 samples per second continuously to disk (aggregate). PowerLab units are compatible with instruments, signal conditioners and transducers supplied by ADInstruments, as well as many other third-party companies. In addition to standard single-ended BNC inputs, 4 differential Pod ports are also available for direct connection of Pod signal conditioners and appropriate transducers. Research PowerLab units include:

Systems

The PL3508B80 Exercise Physiology System is a complete physiology recording system for monitoring cardiorespiratory and metabolic function during exercise. The system records and displays continuous real-time measurements of metabolic parameters such as CO2 and O2 concentrations, airflow, air temperature, ECG or EMG.
The Exercise Physiology System includes:
The MLE1201 BioHarness Telemetry System- EURO and MLE1202 BioHarness Telemetry System- USA can be used for wireless recording of a range of human biopotentials including ECG, heart rate, breathing rate, depth of breath, skin temperature, posture and activity. The BioHarness System components include:

Instruments

The ML206 Gas Analyzer can be used for the measurement of respiratory gas concentrations from small animals, such as rats, through to humans. It contains an infrared carbon dioxide sensor and optical oxygen detector fed from a damped microvacuum sampling pump.
 
The BioHarness ISM Modules (EURO and USA) are used in exercise physiology studies to measure a range of human biopotentials wirelessly via radio frequency. They are suitable for connection to the following chest straps:

Transducers and Accessories

The PTK25 Polar Wireless Heart Rate Kit  offers wireless connectivity (1.2 m range) to a PowerLab data acquisition system for accurate real-time measurement of heart rate from moving subjects.
 
Other instruments and transducers that can be interfaced with a PowerLab such as oximeters, blood flow meters, pulse transducers, goniometers, force transducers, and temperature sensors are available to record a wide range of relevant parameters (see other application pages for further information).

Peripheral Devices

Any third-party device (i.e. ergometer, exercise bike, treadmill) with an analog output (+/- 10V) can be connected to the PowerLab data acquisition system for synchronization of events in LabChart.

Effect of thoracic gas compression and bronchodilation on the assessment of expiratory flow limitation during exercise in healthy humans
Guenette J.A., Dominelli P.B., Reeve S.S., Durkin C.M., Eves N.D. and Sheela A.W., Respiratory Physiology & Neurobiology, 279-286, 2010

Regular endurance exercise in young men increases arterial baroreflex sensitivity through neural alteration of baroreflex arc
Komine H, Sugawara J, Hayashi K, Yoshizawa M, Yokoi T, Journal of Applied Physiology, 1499-1505, 2009

Sex differences in the resistive and elastic work of breathing during exercise in endurance-trained athletes
Guenette JA, Querido JS, Eves ND, Chua R, Sheel AW, American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, R166–R175, 2009

Citations Database


The material on this page is provided in good faith and believed accurate at the time of writing. No responsibility will be taken, or liability accepted, for damages arising from the use of information herein. Readers are urged to check with respective manufacturers the accuracy of all product related information.

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