When you think about your health, you probably think about the physical condition of your body, the kinds of activities you are able to do, and maybe about the food you eat.

But do you ever think about how your health might be affected by where you live? You will investigate that question in this activity.

Consider the relationship between your health and where you live. Life expectancy is an average age to which people are expected to live. It is based on where you live and the history of how old people from that area generally live to be.

Look at the map below.

The map shows that the part of the world in which you live directly affects life expectancy. Average life expectancy is one of the measures people use to determine how healthy a region or country is. The map shows a great difference in the average life expectancy of people around the world:

• In Canada, the United States, Australia, most of Western Europe, and Japan (shown in red on the map), people can expect to live to be at least 75 years of age.

• In most of Eastern Europe, Asia, and some parts of northern Africa as well as Brazil (shown in green on the map), people can expect to live to between 65 and 75 years of age.

• In most of Africa (shown in purple on the map), a person's life expectancy is below 60 years of age.

Why is there such a difference in the average life expectancy among these countries and regions of the world? You will find answers to this question in the activities that follow.

If you were born in Sierra Leone, a country in western Africa, you could expect, on average, to live only 50.8 years if you are a female and 49.3 years if you are a male.

At the other end of the scale, the place in the world with the highest average life expectancy is Japan, where on average, females live for 86.8 years and males live for 80.5 years.

Why would a person in one place in the world be expected to live close to forty years longer than a person in another country?

There are many reasons for differences in life expectancy, but here are a few that you might think of:

• Lack of food resulting in famine or starvation is a major factor in many countries with low life expectancy.

• War obviously affects the average life expectancy of a population. Countries that are involved in civil war (conflict within the country itself) or are at war with neighbouring countries certainly have lower life expectancies than countries not involved in war.

• Disease has a devastating impact on a country's population. You may have heard of the Ebola virus, which greatly reduced life expectancy in many countries, especially in Africa, in countries such as Sierra Leone.

• Lack of health care and health education can also account for low life expectancy. If a person cannot be treated for an illness, that person's chance of dying is much greater than if the person could get treated.

These issues are often related to economic situations. In general, people who live in wealthier countries tend to have a greater life expectancy than people who live in poorer countries.