Effect of Exercise on Gas Exchange

Important Terms and Formulas Minute ventilation Tidal volume Oxygen Uptake/Volume of Oxygen (VO2) Volume of Carbon Dioxide (VCO2) Minute ventilation = Breaths/min x tidal volume VO2 = minute vent. x (% inhaled O2 - % exhaled O2)

Activity In this activity we are going to examine the effect that exercise has on the respiratory system

Activity Before we start, we must realize that we are limited slightly by the equipment (or lack of equipment) that we have. So in order to make some calculations, we will have to make a few assumptions. Here they are: Resting tidal volume = 500 ml Exercising tidal volume = 1000 ml Composition of Inhaled Air = 21% Oxygen, .039 % CO2 Composition of Exhaled Air = 16 % Oxygen, 5% CO2

Part 1 Resting: Select a group member Have them sit in a chair and relax for 1 minute Count the number of breaths they have in 1 minute and record. Using the assumptions on the previous page, calculate the amount of Oxygen getting into their body in 1 minute. This is called their minute ventilation

Part 2 Exercise: The subject will stand in front of a chair and step up and down on the chair for two minutes at the pace Mr. Herb controls. Another person in the group will hold the chair in place so it does not move. As soon as he/she is finished, count the number of breaths he/she takes in 30 seconds and multiply by two to get breaths per minute. Calculate minute ventilation after exercise

Results Complete this table as a class Name Resting Breath Rate Minute Ventilation Resting VO2 Hazlini 20 10 L 500 ml Dung 24 12 L 600ml Mark 13 6.5 L 325 ml Monica 18 9 L 450 ml

Exercise Breathing Rate Exercise Results Name Exercise Breathing Rate Minute Ventilation Exercise VO2 Hazlini 69 69 L 3.45 L/min Dung 39 39 L 1.95 L/min Mark 24 24 L 1.2 L/min Monica 54 54 L 2.7 L/min Average

Analysis What effect did exercise have on breathing rate? What effect did exercise have on VO2? Why? Why is it important for athletes to be able to take a lot of oxygen into their body? Extension Which way does CO2 go during breathing? Calculate the VCO2 for rest and exercise just like you did for VO2. Describe the effect of exercise on VCO2.