The everyday activity that can reveal your brain's age

The speed at which you walk can reveal profound insights into your brain's rate of ageing – with slower walkers having smaller brains and fundamental differences in crucial structures.

It might seem trivial, but how quickly you can walk from A to B can reveal a great deal about the inner workings of your body and mind. Research has shown that the speed at which you walk to the shops, the local park, or the bus stop, can predict your chance of being hospitalised, suffering a heart attack, and even dying. In fact, a person's gait speed can even be used to reveal their rate of cognitive ageing.

The walking speed test is a way of assessing someone's functional capacity –  their ability to perform daily tasks around the house and maintain independence. It can also reveal how frail a person is, and predict how well they will respond to rehabilitation after a stroke.

Although it is normal for people to walk more slowly as they age, a precipitous decline in the speed of someone's gait could indicate that something more serious is going on.

"When a person's normal walking pace declines, it is often associated with underlying health declines," says Christina Dieli-Conwright, a professor of medicine at Harvard Medical School, who studies the effects of exercise on cancer prognosis.  It might be that the person has a chronic condition which has meant that they haven't been moving as much or have become sedentary. That means that, more than likely, they've experienced a decrease in muscle strength, and joint mobility, which unfortunately leads to further health declines," says Dieli-Conwright.