The ageing process Tom Kirkwood What makes our bodies age and how are medical advances making a difference to how long we live?

In this article

Age limits Why we age

Role of genes Lifestyle factors

Uncertain future

Modern health, medicine, sanitation and lifestyle have done remarkably little to extend the overall maximum lifespan of the human species, but they have made a difference to the number of people reaching old age in good health.

Ageing is the result of a build-up of damage in our bodies' cells

Ageing is the result of a build-up of damage in our bodies' cells. It takes a long time for the damage to get to a level where it may harm us, but eventually we can no longer overlook it.

The protein fibres keeping our skin and artery walls elastic go through changes that lead to loss of that vital flexibility. The DNA strands inside our cells get damaged, too. Ultimately, the cells' energy production systems fail.

An important type of damage is oxidisation, the result of attacks by free radicals. Oxidisation rusts metal, makes fat go rancid and causes browning of peeled fruits and vegetables. It also helps to make us age.

Our bodies have evolved powerful antioxidant enzymes to guard cells against free radicals, but these defences aren't 100 per cent.

Longevity tends to run in families. The genes influencing the ageing process seem to be those that influence how well the body maintains and repairs its cells.

The risk of age-related diseases such as Alzheimer's also appears also to have a genetic component.

We can control some aspects of the process

Ageing isn't all down to our genes. We can control some aspects of the process.

The lifestyle choices we make are important. We can eat food that burdens our bodies with saturated fats, for example, or we can eat food that's high in natural antioxidants to aid the body's defences.

We can exercise so our natural systems for renewal and repair keep our muscles, lungs and blood circulatory system in good shape, and we can stretch our minds to reinforce the networks of connection between brain cells.

We know ageing catches up with all of us in the end, but we don't know exactly what lies in store.

Some people keep their mental faculties intact until they're 100, while others can get dementia in their 50s. Some people retain their mobility, but others with conditions such as arthritis find it more difficult.

This article was last medically reviewed by Dr Rob Hicks in July 2007.
First published in March 2000.