Effect of Activity on Requirements for Oxygen and Output of CO2

Baseline Metabolism and Balanced Equation for Respiration

Respiration is the process by which organisms convert glucose and oxygen into energy, producing carbon dioxide and water as waste products.
The balanced equation for aerobic respiration is: C6H12O6 + 6O2 → 6CO2 + 6H2O

Impact of Activity on Oxygen Requirements

Increased activity levels raise the body’s demand for energy and, subsequently, the demand for oxygen necessary for aerobic respiration.
Oxygen uptake is directly related to the intensity of the activity, and heavy exercise can increase oxygen uptake by 15-25 times the resting level.
The human body has adaptations to facilitate increased oxygen intake, such as an increased heart and breathing rate during exercise.

CO2 Output During Exercise

An increased demand for oxygen for energy production during exercise also results in increased carbon dioxide (CO2) output.
CO2 is a waste product of respiration and needs to be removed from the body.
Exercise increases the rate of respiration, hence the rate of CO2 production.
The body expels CO2 more rapidly during exercise through breathing heavily and more frequently.

Homeostasis and Recovery After Exercise

After exercise, the body works to restore homeostasis – the stable internal environment.
The body may continue to consume more oxygen than at rest, known as Excess Post-exercise Oxygen Consumption (EPOC) or the ‘oxygen debt’.
This excess oxygen is used to restore the body to its pre-exercise state, including the removal and breakdown of lactic acid (built up during strenuous exercise), replenishing energy stores and returning the heart and breathing rates to normal.

Remember, understanding how physical activity affects the human body’s demand for oxygen and CO2 output can give insights into respiratory and cardiovascular health and can inform personal exercise, health habits, and lifestyle choices.