CO2 Tolerance Test

Aerobic Capacity, Longer times are better

The CO2 Tolerance Test measures aerobic capacity by measuring how quickly the lungs are depleted through exhaling.

Equipment Required: Stopwatch or timer


  1. Participant takes a full breath in the following manner: A 3-5 second inhale, followed by a 5-10 second relaxed exhale, followed by a 1 second pause.
  2. Participant then repeats this process a further 3 times. At the top of the 4th inhale when their lungs are totally full, the participant starts the stopwatch and exhales as slowly as possible. It may be helpful for the participant to close their eyes so that they can stay relaxed more effectively.
  3. Participant stops the timer when their air runs out, or they feel the need to inhale.
  4. Participant inputs the total time that they were able to exhale for into SharedGoals by clicking on the green “Add score” button.