Name:____________________________________________________________        Per:_______        Date:_______________

Monitoring of Ventilation & Heart Rate in Humans at Rest and After Mild and Vigorous Exercise  (IB Practical 6)

Background

The amount of air that is flushed in and out of the lungs varies substantially depending on the conditions of inspiration and expiration.  Several different respiratory volumes can be described.  Specific combinations (sums) of these respiratory volumes are known as respiratory capacities.  The instrument that is used to measure respiratory volumes is called a spirometer.

Respiratory Volumes

• During quiet breathing, the tidal volume (TV) is the amount of air that moves in/out of the lungs with each breath.  
• The amount of air that can be inspired forcibly beyond the tidal volume (2100-3200 mL) is called the inspiratory reserve volume (IRV).  
• The expiratory reserve volume (ERV) is the amount of air – about 1200 mL – that can be evacuated from the lungs after a tidal expiration.  
• Even after the most strenuous expiration, about 1200 mL of air still remains in the lungs.  This is the residual volume (RV).  

Respiratory Capacities (as noted above, the respiratory capacities always consist of two or more lung volumes)

• The inspiratory capacity (IC) is the total amount of air that can be inspired after a tidal expiration.  It is the sum of the tidal volume and the inspiratory reserve volume.  
• The functional residual capacity (FRC) is the combined residual and expiratory reserve volumes and represents the total amount of air remaining in the lungs after a tidal expiration.  
• Vital capacity (VC) is the total amount of exchangeable air.  It is the sum of the tidal, inspiratory reserve, and expiratory reserve volumes.  We will gauge VC as the maximum amount of air a person exhales after filling his/her lungs to the maximum amount possible.  In healthy young people, VC is approximately 4800 mL.  
• The total lung capacity (TLC) is the sum of all lung volumes and is normally around 6000 mL in young adults.  Lung volumes and capacities tend to be smaller in women than in men because of women's smaller size.

Spirometry

Because the various lung volumes and capacities are often abnormal in people with pulmonary disorders, they are routinely measured in such patients with a device called a spirometer.  Spirometry does not provide a specific diagnosis.  

For this Laboratory experiment you will be using a Voldyne Spirometer.  It is crucial that you use the spirometers carefully (please!) and correctly!  Many factors affect lung capacity, and each individual has a unique combination of them.  Some of these factors include the subject’s anatomical build, the position of the body during the measurement, the strength of the respiratory muscles, the distensibility of the lungs and rib cage, and whether or not the individual has a respiratory infection.  Our goal is to explore how tidal volume and/or vital capacity change as a function of exercise intensity.

Pre-Lab:  Design an experiment to explore how heart rate, tidal volume and/or vital capacity change as a function of exercise intensity.

After reading through this lab:

1. Identify your team's investigative question
2. Design a procedure you will use (should be modified from given procedures)
3. Create a team data table after reading the procedure on the next page.

1. Include title, column headings, uncertainties for measurements
2. Heart rate  +/- 1 beat per minute
3. Spirometer +/- 125 ml

Materials:  

• Voldyne Spirometer (1 per group)                                Cleaning wipes
• Subject wearing exercise clothing and shoes
• Cleaning wipes

How to Monitor Ventilation and Heart Rate at Rest:  ALL GROUP MEMBERS

1. Sit quietly for two minutes.  
2. Place the index and middle fingers of your hand on your wrist (thumb side).  Find and record the pulse (in bpm) of your radial artery.
3. Hold the spirometer at its base. Don't block the air holes (3).  Pinch your nostrils with your free hand to keep air from escaping through your nose.  Sit up straight.  Look straight ahead, without bending over.  
4. To measure tidal volume, place the mouthpiece loosely between your lips and breathe normally through the corner of your mouth (not the mouthpiece) for several breaths to establish a normal breathing pattern.  Then, inhale five successive times into the spirometer.  Try to inhale the amount of air you would normally inhale, though you may have to use a little more force than normal to activate the spirometer mechanism.
5. Record the reading for the total of five breaths and divide by five to calculate the average tidal volume in mL.
6. To measure vital capacity, pinch your nose, sit up straight, inhale as deeply as possible and then – without pausing, exhale as much as you can through the spirometer.  Be careful to avoid leakage around the edge of the mouthpiece.  Empty your lungs as completely as possible over a time span of 5 or 6 seconds.  Record the value shown on the spirometer gauge.
7. Wait 15-30 seconds and repeat this vital capacity measurement.  Wait 15-30 more seconds and repeat the vital capacity measurement a third time.  The largest volume exhaled in your "best" trial (not the sum, not the average) is your vital capacity in mL.
8. When switching users, use an alcohol pad to disinfect the inside of the spirometer.

How to Monitor Ventilation After Exercise (Design Lab)

• Pick one group member to act as your victim subject.  
• The group needs to agree on a mild exercise to perform - keep consistent pace and time while performing it.

•  How will you control for pace and time? How many trials will you do?

• Immediately after this mild exercise, have the subject repeat steps #1-8 above.
• Allow the victim subject to rest for two minutes.  
• Now, they needs to vigorous exercise of your choosing for a set amount of time

• How will you control for pace and time? 

• Immediately after exercising vigorously, have the subject repeat steps # 1-8 above.  

• How many trials will you do?

Data Processing

• Record data in a spreadsheet of your creation.  
• Calculate the mean, standard deviation, and SEM for each set of data.
• Display the processed data with bar graphs.
• Use a statistical t-test (or another kind of statistical test based on your investigative question) to determine is the relationship between your dependent variable and intensity of exercise is significant.

• For a t-test: State your Ho (null hypothesis) and HA (alternate hypothesis)
• Determine your degrees of freedom (n - 2)
• Calculate your t-value and compare that to your critical value at a p value of 0.05
• If the calculated t-value is greater than or equal to this critical value, then the null hypothesis is rejected.  If the calculated t-value is less than this critical value, the null hypothesis is not rejected. What does it mean if your null hypothesis is rejected?

• Write a caption for all data tables and graphs explaining what they show and how you addressed uncertainty within them.

Monitoring Ventilation and Heart Rate Data Blitz

Complete a Data Blitz for your research and findings using the rubric provided. Be sure your slide has:

1. Descriptive Title (the effect of the independent variable on the dependent variable; clearly indicates the research question)
2. Claim (What is the answer to your research question?)
3. Results 

1. Data table (sufficient and appropriate statistically analyzed data)
2. Graph (appropriately selected chart)

4. Conclusion (brief statement suggesting how evidence supports your claim; include a parenthetical citation)
5. Citation(s)

Submit your Data Blitz to Google Classroom and stay tuned for presentation dates.

* If we do not present in class, you will solely be graded on scientific content and slide content.

Ventilation Lab DataBlitz Scoring Guide

Names: ________________________________________________________________________________________________________________________________________________________________________________________________________________________

Title of Presentation:  __________________________________________________________________________________________

RAW SCORE _______/12        CONVERTED SCORE ________/4

General Comments: