Their study, published in the journal Neurology, looked at 121 people aged over 60, around half of them in the early stages of the disease.

Those with Alzheimer’s who were less fit had four times more signs of brain shrinkage than those who were fit.

The Alzheimer’s Research Trust said other research showed exercise reduced the risk of dementia.

“People with early Alzheimer’s disease may be able to preserve their brain function for a longer period of time by exercising regularly” Dr Jeffrey Burns University of Kansas School of Medicine

Some 700,000 people in the UK are living with dementia, with this number predicted to grow quickly over the next two decades, as the proportion of older people in the population increases.

Other studies looking at the relationship between dementia and exercise tend to focus on whether being active can reduce the risk of the condition developing in the first place.

Dr Jeffrey Burns, from the University of Kansas School of Medicine, said his was one of the first to look at whether exercise could affect the progress of the illness.

His volunteers underwent a treadmill test to see how fit they were and then their brains were scanned for shrinkage, which is one way of measuring the severity of their Alzheimer’s.

Brain volume

While there was no relationship between brain size and exercise in people tested who did not have Alzheimer’s, Dr Burns said the four-fold difference in those who did was evidence that exercise might help.

He said: “People with early Alzheimer’s disease may be able to preserve their brain function for a longer period of time by exercising regularly and potentially reducing the amount of brain volume lost.

“Evidence shows decreasing brain volume is tied to poorer cognitive performance, so preserving more brain volume may translate into better cognitive performance.”

Susanne Sorensen, head of research at the Alzheimer’s Society, said: “Exercise increases blood flow to the brain, delivering oxygen and nutrients to brain cells.

“This is one possible explanation why dementia progresses slower in people who are physically fit.

“Exercise also reduces your risk of developing dementia so it’s important to take regular exercise. A healthy heart means a healthy brain.”

Rebecca Wood, chief executive of the Alzheimer’s Research Trust, said: “This adds to previous research showing that exercise helps reduce the risk of dementia and slows down its onset.

“A balanced diet and regular exercise can improve the quality of life of older people with dementia, as well as those who do not have the condition.”

News reported by The BBC

Alzheimers Research Trust
Alzheimers Society

A study of 900 people aged over 60 found early onset was most likely in those who also had a high-risk gene.

A second US study found people with high cholesterol in their early 40s are one and a half times more likely to develop Alzheimer’s.

The research was presented at an American Academy of Neurology meeting.

It has been estimated that a delay in the onset of Alzheimer’s disease by five years would lead to a 50% drop in the number of cases.

“It’s possible that if we can reduce or eliminate heavy smoking and drinking, we could substantially delay the onset of Alzheimer’s disease for people and reduce the number of people who have Alzheimer’s at any point in time” Dr Ranjan Duara

The researchers said their findings showed heavy drinking and smoking were two of the most important preventable risk factors for the condition.

Those taking part in the study had been diagnosed with possible or probable Alzheimer’s disease and smoking and drinking history was obtained from family members.

Risk factors

Heavy drinking, defined as more than two drinks a day was found to lead to an almost five-year earlier onset of Alzheimer’s.

And those who smoked more than 20 cigarettes a day developed the disease two years sooner.

People with a specific gene – APOE variant 4 – developed Alzheimer’s disease three years earlier than those without the gene variant.

All three risk factors together were associated with onset of the disease 8.5 years earlier than those with none of the risk factors.

Study leader, Dr Ranjan Duara, from Mount Sinai Medical Center in Florida said: “It’s possible that if we can reduce or eliminate heavy smoking and drinking, we could substantially delay the onset of Alzheimer’s disease for people and reduce the number of people who have Alzheimer’s at any point in time.”

In the second study, 9,700 men and women were followed from the age of 40.

Those with cholesterol levels higher than around six millimols per litre (mmol/L) had a one and a half times higher risk of developing Alzheimer’s than those with low cholesterol.

“High mid-life cholesterol increased the risk of Alzheimer’s disease regardless of diabetes, high blood pressure, obesity, smoking and late-life stroke,” said researcher Alina Solomon.

Dr Susanne Sorensen, head of research at the Alzheimer’s Society said the research added to the weight of evidence on drinking and smoking habits and the risk of developing dementia.

“The best way to reduce your risk is to eat a balanced diet rich in antioxidants and vitamins and to exercise regularly.

“Not smoking, drinking only in moderation and getting your blood pressure and cholesterol checked regularly throughout life are also important ways people can reduce their risk of dementia.”

News reported by The BBC

Alzheimers Research Trust
Alzheimers Society