1. Respiratory System
DEFINTION: This is the system that breathes in oxygen and exhales carbon dioxide. The main organs are the lungs.
During exercise the respiratory system is in charge of delivering oxygen to the heart (which then sends it round the body) whilst also getting rid of carbon dioxide.
- Tidal Volume: normal breathing (in and out).
- Vital Capacity: the maximum amount of air you can forcibly breathe in and out in one breathe
- Lung Capacity: the total volume of air in your lungs after your biggest breath in.
- VO2 Max: the maximum of oxygen you can take in per minute.
- Oxygen Debt: a temporary shortage in oxygen (occurs after anaerobic exercise).
Respiratory System (GCSE PE: Unit 1.2.2)

2. Immediate Effects of Exercise on the Respiratory System
These things happen as soon as the body starts exercising.
They all happen because the body needs more OXYGEN to send to the heart (to then be pumped to the muscles)
Breathing gets quicker & deeper: this increases the amount of oxygen taken into the lungs with each breath and increases the removal of carbon dioxide.
Increased Tidal Volume: Quicker and deeper breathing means tidal volume increases.
Oxygen Debt occurs: Anaerobic exercise sometimes means oxygen cannot be supplied quickly enough through breathing (because the activity is so quick – sprinting). This means, when you stop, you need to make up for the lack of oxygen (the oxygen debt) by taking big, gasping breaths.
Respiratory System (GCSE PE: Unit 1.2.2)

3. Long Term Effects of Exercise on the Respiratory System
These things happen when the body has been exercising over a long period (e.g. 6 months).
1. Improved Lung Efficiency: trained lungs are more efficient at delivering oxygen through the lungs. BENEFIT: More oxygen gets to the working muscles.
2. Number of Alveoli Increase: Exercise helps to increase the number of alveoli (little air sacs) in the lungs. BENEFIT: More oxygen can be breathed into the lungs with every breath (meaning VO2 max also increases). More oxygen can be absorbed into the blood vessels (capillaries).
3. Capillarisation: Increase in the number of blood vessels (capillaries) around the alveoli. BENEFIT: So more oxygen can be absorbed in the blood and be delivered to the working muscles.
4. Increased Vital Capacity: Lungs can inhale and exhale more air.
Respiratory System (GCSE PE: Unit 1.2.2)

4. Lifestyle Effects on the Respiratory System
There is one main lifestyle factor that can have an effect on the respiratory system.
Smoking: Smoking can lead to a number of problems to do with the respiratory system:
Potentially lead to diseases such as: bronchitis, emphysema and lung cancer.
It damages the alveoli: The walls of the alveoli get broken down meaning less oxygen can be diffused into the capillaries with each breath.
It increases blood pressure.
It effects exercise: Because alveoli are damaged and less oxygen is diffused there is less oxygen to send to the working muscles. This means the performer becomes tired and is unable to perform to a high ability.
Respiratory System (GCSE PE: Unit 1.2.2)