Exercise, asthma and smoking

Describe the short-term effects of exercise on breathing and heart rate and explain why these changes occur.
Explain how asthma affects the airways and the efficiency of gas exchange in the lungs.
Describe the damaging effects of smoking on the respiratory system, including the impact of tar and carbon monoxide on gas exchange.

Your muscles work harder during exercise and need much more oxygen to release energy.
They also produce more carbon dioxide as a waste product, which needs removing.
What happens?
1. You breathe more deeply to get more air (and oxygen) into your lungs with each breath.
2. You breathe faster (increase your breathing rate) to speed up the intake of oxygen and removal of carbon dioxide.
3. Your heart beats faster to pump blood around your body more quickly, delivering the oxygen and taking away the carbon dioxide efficiently.
Regular exercise makes your lungs and heart stronger and more efficient at their jobs.

Asthma is a common condition that affects the tubes carrying air into the lungs (the bronchi and bronchioles).
In people with asthma, these airways can become sensitive and inflamed.
Certain triggers (like pollen, dust, cold air, or exercise) can cause the muscles around the airways to tighten, the lining to swell, and extra mucus to be produced.
Impact on Gas Exchange:
- This narrowing of the airways makes it difficult for air to get in and out of the lungs.
- Less oxygen reaches the alveoli, making gas exchange less efficient and causing wheezing and shortness of breath.
People with asthma often use inhalers containing medicine to relax the airways and make breathing easier.

Smoking cigarettes is extremely harmful to the gas exchange system. Cigarette smoke contains thousands of chemicals, including:
Tar:
- A sticky, black substance that coats the lining of the airways and alveoli.
- It damages the tiny hairs (cilia) that normally sweep mucus and trapped dirt out of the lungs. This leads to mucus build-up and 'smoker's cough'.
- Tar covering the alveoli reduces the surface area available for efficient gas exchange.
- It also contains cancer-causing chemicals (carcinogens).
Nicotine:
- A highly addictive drug that makes people want to keep smoking. It also raises heart rate and blood pressure.
Carbon Monoxide:
- A poisonous gas also found in car exhaust fumes.
- It enters the blood and reduces the amount of oxygen that red blood cells can carry around the body. The heart has to work harder to supply enough oxygen.
Smoking can lead to serious lung diseases like bronchitis (inflamed airways with lots of mucus), emphysema (damage to the alveoli making them less efficient), and lung cancer.
It severely damages the gas exchange system, making breathing difficult and reducing the body's oxygen supply.

Gas exchange: The process of taking oxygen into the blood and removing carbon dioxide, which occurs in the lungs.
Exercise: Physical activity that increases the body's demand for oxygen and energy.
Breathing rate: The number of breaths taken per minute.
Heart rate: The number of times the heart beats per minute.
Asthma: A respiratory condition where the airways become inflamed and narrowed, making breathing difficult.
Airways: The tubes (trachea, bronchi, bronchioles) that carry air to and from the lungs.
Smoking: The act of inhaling smoke from burning tobacco, which contains many harmful chemicals.
Tar: A sticky substance in cigarette smoke that damages airways and reduces the surface area for gas exchange in the alveoli.
Carbon Monoxide: A poisonous gas in cigarette smoke that reduces the blood's ability to carry oxygen.

Investigate in more detail how different intensities of exercise affect breathing rate and heart rate, and explain how these changes help supply the muscles with enough oxygen.
Research strategies for managing conditions like asthma (e.g., using inhalers, avoiding triggers) or explore the health benefits for the respiratory system of quitting smoking.