Keeping Healthy

Key facts: In order for a body to keep healthy it’s important to have a balanced diet and to exercise on a regular basis. If somebody eats too much and doesn’t exercise enough then they’re more likely to become overweight, which can lead to a number of different illnesses. On the other hand, if someone eats too little then this can lead them to become underweight, which is also connected to a range of health disorders.

Diet and Exercise

By the end of this section you should understand:

• how food affects health
• in what ways lifestyle plays a part in disease development

The importance of a balanced diet

In order to have a healthy body it’s important to eat a mixture of different types of food. Food is composed of three main components:

• carbohydrates
• fats
• proteins

These are used by the body for energy and other functions. A healthy body also needs a small amount of mineral ions and vitamins.

The dangers of an imbalanced diet

A person who doesn’t maintain a balanced diet is malnourished. Malnourishment can cause someone to be either underweight or overweight. It can also lead them to develop deficiency diseases, for example rickets which is caused by too few vitamins, or other medical conditions such as Type 2 diabetes.

NOTE: For your exam you don’t need to learn how nutrients function or how the body is affected by deficiencies in the diet.

By the end of this section you should understand:

• how Semmelweiss helped to control infection and how this idea is used to control infections in hospitals today
• how our understanding of how immunity and antibiotics has changed how disease is dealt with
• how epidemics and pandemics are caused by bacteria and virus mutations
• what the advantages and disadvantages to vaccinations are

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The Effects of Exercise

If the energy taken in from food is less than the energy used by a person then their body mass decreases. Exercise is one way of increasing how much energy is being used up. Energy is released from food by the cells in a chemical reaction known as respiration. The speed at which these chemical reactions take place is called the metabolic rate. The amount of physical activity you do and the ratio of fat to muscle you have will affect this rate.

Not only does the metabolic rate increase during exercise but it continues like this afterwards as well. In general, somebody who exercises regularly is healthier than someone who doesn’t.

There are a number of other factors which can affect this speed including:

• age
• gender
• inherited factors, for example cholesterol levels in the blood

NOTE: You don’t need to know how the breathing and heart rate is affected by exercise.