Submaximal exercise and energy expenditure laboratory - semester 1, session 1

Health and safety guidelines:

  • Do not touch anything other than the equipment that you are using when wearing disposable gloves (ie. Face, watch, mobile phone)

  • Disposable gloves must be worn when handling bodily fluids (eg. Blood, saliva, urine)

  • Gloves must be disposed of the yellow biohazard bins (needles must go in the sharps bin)

  • No food or drink brought into or consumed in the lab (other than exercising participants being allowed to drink)

 

Rules, regulations, and guidelines of good practice for working within a lab environment:

  • Health and safety regulations

  • Participant safety and ethical guidelines (informed consent, explain procedures, monitoring of participants)

  • Laboratory hygiene and infection control (washing hands, PPE, disinfect surfaces and equipment)

  • Equipment safety and calibration (treadmills, cycle ergometers, ECG systems, gas analysers, spirometers, force plates)

  • Professional conduct and behaviour

  • Emergency procedures (fire evacuation and first aid)

  • Data protection and record keeping

 

Basic data collection at rest and during exercise using equipment:

Resting procedures

Preparation:

  1. All participants complete an informed consent form and general health screening before starting the experiment

  2. Evacuate all Douglas bags and connect a Falconia tube/mouthpiece to the first empty bag. Record the ambient (room) temperature (°C) and pressure (mmHg) (to evacuate the Douglas bag, open the valve on the Douglas bag (vertical position) then turn on the pump and monitor the numbers on the dry gas, then close the Douglas bag valve and turn off the pump)

  3. Fit a HR monitor to the participant and check that the heart rate is displayed

Resting sample:

  1. The participant adopts a seating position

  2. Ask the participant to place the nose clip comfortably and then to position the mouthpiece ready for sample collection and allow 2-3 minutes for habituation. Once habituated to the equipment, start the clock for a 5-minute rest period

  3. The expired air sample is collected over the entire 5-minute period (coordinate opening the valve on the Douglas bag with starting the timer (turn valve clockwise so it is in the vertical position). Once timer is up, turn valve anticlockwise so it is back in the horizontal position)

  4. During the final 30 s of each minute, record HR every 5 s and calculate the mean

  5. Record fB for each minute (breathing frequency - breaths per minute)(observe breathing chamber by watching the valve open and close or the appearance and disappearance of a cloud of condensation in the breathing chamber

Sample analysis:

  1. Analyse the Douglas bag as soon as the expired air sample has been collected (connect servomex gas analyser to the Douglas bag. Screw the sampling tube to the right hand end of the sampling rig on the top of the Douglas bag carousel (this white valve should be pointing through the tubing and the colour-coded valves for the Douglas bags should be in the closed position)). Coordinate the starting of the timer with the opening of the valve and starting the servomex gas analyser. Flow rate meter shows the rate at which air is being removed from the Douglas bag - record this as it allows you to calculate the total bag volume as this is the air that is taken out for sampling. The servomex screen will display the fractions of expired oxygen and carbon dioxide)

  2. Evacuate the Douglas bag and make a note of the temperature and the volume of expired gas

  3. Calculate VT (volume of one single breath) by using the equation: VT = VE ÷ fB

Exercise procedures - submaximal testing

  1. Adjust the seat height on a Monark cycle ergometer so that the participant can cycle comfortably with a knee angle of ~160-170 degrees with the pedal in the down stroke

  2. The participant cycle continuously for 16 min at a constant cadence of 60 rpm whilst the applied load is increased progressively, every 4 min (ie. 4 x 4 min exercise stages)

  3. Terminate the data collection procedure and continue to monitor the participant during their cooling down period

  4. In the final minute of each stage measure expired air sample, breathing frequency, flywheel revolutions, RPE, HR every 5 seconds (calculate mean)

  5. Analyse expired air samples once protocol is complete

  6. Determine FEO2 and FECO2(%) (Servomex) and air volume and temperature (Dry gas meter)

 

Why must gas volume be corrected for ambient conditions?

To standardise gas volumes for accurate comparisons between physiological data collected as VEATPS is ambient temperature and pressure, saturated with water vapour whereas VESTPD is standard temperature, pressure, and dry

 

Why is the Haldane transformation applied?

The Haldane transformation is applied because nitrogen is not exchanged in the lungs. By assuming inspired nitrogen equals expired nitrogen, physiologists can calculate inspired ventilation and accurately determine oxygen consumption and metabolic variables from expired gas measurements