Health and Prevention
Issue — How can we understand the mechanisms that influence our health and how can we act to protect it?
- Understand what health means in a broad sense.
- Identify factors that can affect health.
- Discover prevention methods to avoid diseases.
- Understand the role of the immune system.
Part 1: What is health?
Health is not just the absence of illness: it is a state of well-being physically, mentally and socially.
Health corresponds to a dynamic balance between the body, mind and environment: it can vary depending on situations (fatigue, stress, illness…).
A person can be physically healthy but suffer from stress or social isolation, which affects their overall well-being.
- Health is a global state that depends on several dimensions (physical, mental, social).
Part 2: Factors that influence health
Several factors can have a positive or negative impact on health:
- Internal factors: genetic, physiological (age, hormones...).
- External factors: diet, physical activity, sleep, environment, lifestyle habits.
- Pathogens: viruses, bacteria, parasites (they can cause infections).
An infection occurs when a pathogen enters and/or multiplies in the body. A disease appears when the infection (or another factor) causes symptoms and disrupts the body's functioning.
- A balanced diet and good sleep promote health.
- Tobacco and alcohol increase the risk of diseases.
- Pathogenic microorganisms can cause infections.
| Type of factor | Possible effect | Examples |
|---|---|---|
| Internal | Predisposition or protection | Genetics, hormones, age |
| External | Improves or worsens well-being | Diet, exercise, sleep, pollution |
| Pathogen | Can trigger an infection | Viruses, bacteria, parasites |
- Health depends on a balance between protective factors and risk factors.
- Pathogens can cause infections, sometimes leading to diseases.
Part 3: Disease prevention
Prevention includes actions that reduce the risk of becoming ill, detect diseases early, or avoid complications.
- Primary prevention: avoid the onset of disease (hygiene, vaccination, physical activity...).
- Secondary prevention: early screening to act quickly (exams, checks, screenings).
- Tertiary prevention: limit complications and help live with a disease (monitoring, treatments, rehabilitation).
- Hygiene: washing hands, airing rooms, reducing transmission of germs.
- Vaccination: trains the immune system to recognize a pathogen.
- Lifestyle: balanced diet, regular physical activity, sufficient sleep.
Flu vaccination reduces the risk of severe forms in some people and limits the spread of the virus.
- Prevention acts before, during, or after disease to protect health.
Part 4: The role of the immune system
The immune system defends the body against pathogens.
Two types of responses
- Innate immunity: a fast response (barriers like skin, inflammation, certain cells that destroy microbes).
- Adaptive immunity: a more specific response (lymphocytes) that can produce antibodies and memory.
After the first encounter with a pathogen (or after vaccination), the body keeps a memory: the response is faster and more effective upon new contact.
After vaccination, the body can recognize the targeted agent faster and fight it more effectively.
- The immune system protects the body through innate and adaptive responses.
- Immune memory explains the importance of vaccination.
Health is a global state influenced by internal factors, external factors, and exposure to pathogens. Prevention (hygiene, vaccination, screening, lifestyle) reduces risks and protects the body. The immune system defends against infections through innate, adaptive responses and immune memory. Adopting a healthy lifestyle and preventive measures helps preserve health sustainably.