Daily power walks in old age cut Alzheimer’s risk

Power walking every day or going for a bike ride can help to reduce the risk of Alzheimer’s in the elderly, according to a new study. While research has previously shown the importance of keeping active in middle age, scientists from the University of California seem to have discovered that it’s never too late to reap the benefits of exercising.

They analysed 167 people who died at an average age of 90 to establish the effects exercising had on the levels of microglia on their brains. This type of cell can cause inflammation, which is thought to contribute to the development of Alzheimer’s.

Tracking began in 1997 and the participants wore activity monitors for up to ten days before undertaking cognitive exams once a year. The scientists measured microglia activation and Alzheimer's disease in the brain after the death of the participants. Some 60 per cent of the individuals had been diagnosed with Alzheimer’s by the time of their death.

It was discovered that those who exercised regularly in old age had less microglia than their peers with more sedentary lifestyles. This could therefore be interpreted as significantly reducing their chances of developing Alzheimer’s and experiencing the related cognitive decline.

This research backs up advice handed out by doctors that suggests healthy adults should be undertaking 150 minutes of moderate exercise each week. This could be in the form of taking brisk walks or going for a gentle bike ride. Those with the ability to accomplish something more vigorous are advised to do 75 minutes of more intense activity each week.

Dr Kaitlin Casaletto, lead author of the study, said: “Microglia, the brain's resident immune cells, activate to clear debris and foreign invaders from the brain. But too much activation can trigger inflammation, damage neurons and disrupt brain signalling. Exercise helps reduce abnormal activation in animals, but that link hadn't been established in humans.”

The part of the brain that is most affected by Alzheimer’s is the inferior temporal gyrus and it was found that microglia here was particularly influenced by an active lifestyle. Exercise had a greater impact on inflammation in individuals with more severe Alzheimer's pathology.

Dr Casaletto added: “These are the first data supporting microglial activation as a physiological pathway by which physical activity relates to brain health in humans. Though more interventional work is needed, we suggest physical activity may be a modifiable behaviour leveraged to reduce pro-inflammatory microglial states in humans.”

Alzheimer’s disease is a form of dementia, which some 920,000 people in the UK are living with. This is expected to rise to two million by the year 2050 and as there’s currently no cure for the condition, lifestyle choices are among the most effective ways for people to protect themselves from developing it.