Health: The Ultimate TreasureClass 8 Science Notes

Health: Is It More Than Not Falling Sick?

Health is more than just not being sick. It involves physical well-being, a positive mindset, and strong relationships. A healthy person takes care of their body, stays positive, and enjoys social life.

According to the World Health Organization (WHO), health is a 'state of complete physical, mental, and social well-being, and not merely the absence of disease.' Being healthy helps you perform tasks efficiently and cope with difficult situations. It also allows you to adjust well with friends and other members of society.

Our Scientific Heritage

Ayurveda teaches us that true health is a balance of body, mind, and surroundings. To maintain this balance, it is important to:

• Follow dinacharya (daily routine) and ritucharya (seasonal routine).
• Eat fresh, wholesome food suited to one's prakriti (body constitution).
• Engage in regular exercise and maintain cleanliness.
• Get restful sleep and maintain a calm mind.

Practices like yoga, meditation, and mindfulness can also support overall well-being.

How Can We Stay Healthy?

Staying healthy involves several key practices:

• Eating nutritious food.
• Maintaining hygiene.
• Staying in a clean environment.
• Exercising regularly.
• Getting proper sleep.
• Spending time with family and friends.
• Maintaining a positive attitude.

Taking care of both our body and mind is crucial, as healthy habits support both a healthy body and a healthy mind. Our health depends on many factors, including our lifestyle (how we live) and our environment (our surroundings).

Maintain a Healthy Lifestyle

To maintain a healthy lifestyle:

• Eat a balanced diet with plenty of fruits, vegetables, and whole grains.
• Avoid processed, fatty, or sugary foods and drinks.
• Stay physically active by playing outdoors, walking, running, cycling, or exercising.
• Limit screen time and spend more time in nature.
• Get enough sleep to help your body and mind rest and recover.
• Practice yoga or simple breathing exercises like pranayama regularly.
• Say 'NO' to harmful substances like tobacco, alcohol, and addictive drugs.

Keep the Environment Clean

Clean air and water are essential for our health. In cities, air pollution from vehicles and factories can cause problems like coughing or asthma. The Air Quality Index (AQI) helps us know how clean the air is. A cleaner environment helps us stay healthy and feel better.

Health is not only about the body. Our feelings and relationships matter too. Even if we eat well and live in a clean place, we may not feel good if we are lonely or upset. Spending time with friends and family, talking, laughing, and having fun help keep our minds healthy too.

How Do We Know That We Are Unwell?

When we feel unwell, it means something inside us may not be working as it should. We may experience symptoms, such as pain, tiredness, or dizziness, and signs like fever, rash, high blood pressure, or swelling.

• A symptom is what we feel (like pain).
• A sign is something that can be seen or measured (like high body temperature when we have fever).

These signs and symptoms help doctors understand what might be making us unwell.

Diseases: What Are the Causes and Types?

A disease is a condition that affects the normal working of the body or mind. It can happen when one or more organs or organ systems stop functioning properly.

Some diseases are caused by germs like bacteria, viruses, fungi, worms, or even by protozoa (single-celled organisms). These disease-causing organisms are called pathogens. Other diseases may result from poor nutrition or an unhealthy lifestyle.

Diseases can be grouped into two major types based on their causes and how they spread:

• Non-communicable diseases: These diseases, like cancer, diabetes, or asthma, are not caused by pathogens and do not spread from one person to another. They are usually linked to lifestyle, diet, and/or environment.
• Communicable diseases: Diseases caused by pathogens are called communicable diseases. They can spread from one person to another. Some examples of communicable diseases are typhoid, dengue, flu, chickenpox, and COVID-19.

In recent years, non-communicable diseases (NCDs) like diabetes, heart disease, and cancer have become more common in India. This is happening because of changes in how people live – such as eating more processed food, getting less exercise, and living longer lives. Today, most deaths in India are caused by NCDs.

How are communicable diseases caused and spread?

All communicable diseases are caused by pathogens. These pathogens can enter our body through the air we breathe or by consuming contaminated food or water.

Pathogens can spread from one person to another through:

• Air (when an infected person coughs or sneezes).
• Direct contact (like shaking hands).
• Indirectly (by sharing personal items of an infected person).
• Contaminated drinking water or food.
• Insects like mosquitoes and houseflies – these insects are called vectors.

By understanding how diseases spread, we can take simple steps to protect ourselves and others. Some simple but important precautions include:

• Keeping ourselves and our surroundings clean.
• Practicing basic hygiene every day.
• Washing hands with soap and water to remove pathogens.
• Covering our mouth and nose while coughing or sneezing.
• Wearing a mask in crowded places provides protection.
• Avoiding sharing of personal items like towels and handkerchiefs.
• Keeping our home, food, and water clean.

Some infectious diseases are caused by worms that live inside our bodies, especially in the digestive system. They feed on nutrients and live as parasites – organisms that live in or on another living being. These worms usually spread through contaminated food, water, soil, or contact with infected people or animals.

How are non-communicable diseases caused?

Non-communicable diseases like cancer, diabetes, and asthma are linked to lifestyle, diet, and/or environment. They are the most common cause of death in India. Diseases like scurvy, anaemia, and goitre, which are caused by a lack of specific nutrients in the diet, are called deficiency diseases and are also non-communicable.

Diseases such as cancer, diabetes, and asthma may often persist for a long time (more than three months) and are referred to as chronic diseases.

Diabetes is a common disease which is becoming more prevalent in adults as well as children. In fact, India now has one of the highest numbers of people with diabetes in the world. It often develops due to a combination of hormonal imbalances, unhealthy eating habits, lack of physical activity, being overweight or obese, and other reasons.

How to Prevent and Control Diseases?

"Prevention is better than cure." It is important to protect ourselves from both communicable and non-communicable diseases.

Simple steps like good sanitation can greatly reduce the spread of communicable diseases.

Ability of the body to fight diseases

The natural ability of our body to fight diseases is known as immunity. Our body has a special system called the immune system that helps fight against diseases.

Vaccines help prevent serious infections caused by viruses and bacteria. A vaccine helps our body fight certain diseases by training the immune system to recognize and attack harmful germs, providing what is known as acquired immunity – protection developed after exposure to a pathogen or a vaccine. Vaccines can be made in different ways – from weakened or dead pathogens (like viruses or bacteria), or from inactive or harmless parts of the pathogen. Some newer vaccines instruct our own body cells to make a harmless part of the germ, which our immune system then learns to fight.

Edward Jenner and the smallpox vaccine

Smallpox was a deadly disease that caused blisters and killed millions. In the late 1700s, English doctor Edward Jenner discovered that people who had cowpox did not get smallpox. This led to the invention of the first vaccine and helped protect people from smallpox.

Long before modern vaccines, India had a traditional method called variolation to protect against smallpox. It involved using material from a smallpox sore to scratch the skin and create a mild infection and build immunity. People who performed this practice were known as teekedaars.

Vaccines are one of the most effective ways to protect people of all ages – from infants to the elderly – against many serious diseases. They help prevent illnesses, reduce the spread of infections, and save millions of lives every year. It is important to remember that vaccines are preventive, not curative – they can help minimize serious diseases before they happen, but do not treat them once someone is already sick. Getting vaccinated not only protects you but also the people around you.

Treatment of diseases

If our immune system fails to protect us against an infectious disease, we fall ill and need to visit a doctor. The doctor may give us medicines called antibiotics, which kill the bacteria that might have caused the disease. Antibiotics work only against bacterial infections because they target parts of bacterial cells that are different from human or other animal cells. They do not work against viruses or diseases caused by protozoa.

Discovery of the first antibiotic, Penicillin

Penicillin was discovered in 1928 by Alexander Fleming. He noticed that a mould on a discarded petri dish stopped the bacteria from growing. He realized the mould released a substance that killed the bacteria. This chance discovery led to the discovery of penicillin, the first antibiotic used to treat bacterial infections.

Though antibiotics are effective in protecting us against bacterial infections and have saved millions of lives since their discovery, their indiscriminate use has led to a decline in their effectiveness. Nowadays, there are news headlines about antibiotic resistance, a phenomenon where bacteria that were earlier killed by a given antibiotic are found to survive and multiply despite treatment with that antibiotic. This makes common infections harder to treat and increases the risk of complications, prolonged illness, and even death.

To tackle the problem of antibiotic resistance, we must use antibiotics wisely – only when prescribed by a doctor, in the correct dose, and for the right duration. Avoiding unnecessary use helps prevent the rise of resistant bacteria and keeps antibiotics effective for future generations.

Traditional medicine systems like Ayurveda, Siddha, and Unani have been used in India for many years to manage common health problems. They use natural substances like herbs, oils, and minerals for managing illnesses and promoting recovery, and focus on a healthy lifestyle and balanced diet. While these systems can help with some conditions, and are useful for everyday well-being, they may not be effective for all diseases and at all stages.

Therapies for non-communicable diseases focus on managing symptoms and improving quality of life through medication, lifestyle changes, and rehabilitation. Early diagnosis and continuous care are key to control the disease progression and prevent complications.