Oxygen is highest on the list of substances required to support human life, followed by water, then food. People may live weeks without food, days without water, but only minutes without breathing. People must breathe constantly, and breathing patterns change depending on the situation, such as during or after exercise. Breathing is the only body function that can be controlled consciously or unconsciously.
Natural breathing automatically maintains a very specific gas ratio of O2 to CO2 in the blood stream; 6.5% CO2 and only 2% O2. Each breath contains 10 times more oxygen and 200 times less carbon dioxide than we need.
It is possible to breathe too much (hyperventilation). When we breathe normally, hemoglobin, the principle carrier of oxygen in the body, remains 98% oxygen (O2) saturated. When we breathe too quickly, we increase O2 saturation slightly but lose too much CO2, which is essential for O2 utilization. When the level of CO2 decreases too much the hemoglobin does not release O2 to the tissues (the Bohr Effect), which causes O2 starvation. The simple remedy is to breathe into a paper bag so exhaled CO2 is re-breathed and the CO2 level in the blood stream is restored.
Hypothesize: Will the CO2 levels of a student’s breath be higher or lower after exercise? Why?
) to begin collecting CO2 data.
) to end the experiment.
) in the Graph toolbar.
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