A science teacher explains: Why do we fall sick?

There are two major kinds of diseases: infectious and non-infectious. Infectious diseases are caused by pathogens such as bacteria, viruses, fungi and parasites entering the body through the air we breathe, the food and drink we consume or through openings in the skin, such as cuts. As an example, through cough and sneezing a person can spread the cold virus to another. Non-infectious diseases are caused by a confluence of factors including the environment, a person’s lifestyle choices and genetics. For example, heart disease may be caused by a sedentary lifestyle and a poor diet, or it may be caused by a family history of the disease.

What happens in your body when you have a cold? How does the body fight cold?

The common cold describes a whole range of more than 200 viruses that target the linings on the inside of your nose, your throat and sinuses and binds to the cell. The virus hijacks the cell to help it make more viruses that go on to infect other cells, preparing to invade more of your nose. At any sign of infection, your cells raise the alarm by sending out messages about the common cold virus. The white blood cells, vessels and brain all read these messages, and focus on the affected areas.

The blood vessels around the affected area widen, allowing more blood to flow into the area and bring more white blood cells to fight the virus. As a side effect, these areas become puffy, red and filled with fluid. The area gets hotter, wetter and less comfortable for the virus to settle in. Some white cells make antibodies which will target future reinvasions by the virus. With a very densely packed, wet and high-pressure environment, your nose starts flowing and your body clears itself from all the used white cells, virus and excess fluid.

What happens to your immune system when you get sick? How does the immune system work?

When a germ that can make you sick (antigen) enters the body, your immune system is triggered and it creates antibodies. Antibodies are a special kind of protein that attach to the antigen and remember it. Other cells in the immune system then come destroy the antigen. The antibodies remain in your body so they will recognise the germs if you are exposed to them again.

How do you strengthen your immune system?

To function well, the immune system requires balance and harmony. Researchers are exploring the effects of diet, exercise, age, psychological stress and other factors on the immune response, both in animals and in humans. General healthy-living strategies are a good way to start giving your immune system the upper hand. Some are as follows:

• Eat a healthy diet high in fruits and vegetables.
• Exercise regularly.
• Get adequate sleep.
• Take steps to avoid infection, such as washing your hands frequently, etc.

Does getting sick strengthen your immune system?

When you get sick, the immune system produces antibodies which remain in the body even after the infection is over and fight if the same kind of antigens develop. This in a way strengthens your immune system. Leading a healthy life is for sure the best way to strengthen one’s immune system.

Why do we sweat after a fever?

Sweating is a cooling technique which brings down the temperature of our body. When we have high fever our brain sends blood near the surface of your skin to release heat, and you cool back down to your normal body temperature.

Why do we feel bad when sick?

The rise in temperature can slow bacteria and help your immune system destroy pathogens. Sleep lets your body channel more energy towards fighting infection. So it’s actually the body’s own immune response that causes much of the discomfort you feel every time you get ill.

(Source: Some inputs have been sourced from science.howstuffworks.com and webmd.com.)

(Meenambika Menon is Lead, Curriculum – Science & Math at Shiv Nadar School.)