Simple lifestyle changes can significantly reduce your risk of dementia, and Dr Emer MacSweeney is an expert who practices what she preaches.

The neuroradiologist co-founded the Re:Cognition Health clinic, which has played a key role in clinical trials that led to breakthrough drugs being approved for use in the UK.

Exercise, diet, sleep and levels of mental stimulation are among factors can influence our risk of developing dementia, Dr MacSweeney said.

She explained: “From the day you’re born, the big modifiable risk factors are exercise and diet. 

“The brain hates sugar, so it’s about keeping to what we call a Mediterranean diet and staying away from sugar in all its formats.”

A recent study concluded that regular exercise such as swimming, running, walking or dancing may preserve brain abilities past the age of 65.

Research involving 648 healthy people aged 65-80 found those with the highest cardiorespiratory fitness (CRF) typically scored higher on five cognitive tests.

When I visited Dr MacSweeney’s Harley Street clinic, we marched up and down several flights of stairs at a pace that got our pulses racing. And it was no surprise - asked for her number one tip, Dr MacSweeney said exercise was the most important factor.

She added: “If you could do three times a week, 30-40 minutes of intensive aerobic exercise, then you can tick that box, although the advice is changing all the time.

“Particularly as people are getting older, don't underestimate the power of walking. If you can walk quickly for 45 minutes every day you’ll feel great, and that’s probably something that most people can do.

The medic also recommended keeping the brain active, perhaps by learning another language or musical instrument, and not drinking too much or smoking.

She went on: “Increasingly people are understanding more about sleep and why it’s so important.

“The other one which so many older people don’t do is hydration. You should be drinking at least two litres of water a day.

“It has been demonstrated now that paying attention to these things will decrease those modifiable risk factors really quite significantly.”