Daily physical activity key to staving off dementia

by Jill Margo for Finacial Review:

Any woman interested in preserving her brain function into old age needs to do one thing above all others, according to a landmark Australian study.

She needs to move and do so regularly. Over all other factors, daily physical activity of any sort is her platinum ticket to staving off dementia, says study leader Cassandra Szoeke , a consultant neurologist and associate professor of medicine at The Royal Melbourne Hospital and The University of Melbourne.

Two-thirds of all cases of dementia occur in women and Szoeke says the simple message is that while many things can help, physical activity is best and the earlier women start doing it, the better.

It is estimated that less than 25 per cent of Australian women engage in sufficient physical activity.

Besides preventing dementia, the study shows physical activity also gives women a better memory in older age. The implications are so powerful they have influenced the way Szoeke runs her own life: "I have changed my behaviour through this research and am I am focusing less on my weight and more on increasing my daily activity."

As the evolution of cognitive decline is slow and steady, the study followed women over 20 years through mid-life. They were given periodic memory tests because memory is one of the first things to decline when Alzheimer's begins to develop.

They all did Episodic Verbal Memory tests in which they learnt a list of 10 unrelated words and then tried to recall them half an hour later.

Any activity is good

Almost 400 women, aged between 45 and 55, were followed. All their lifestyle factors, including diet, education, marital and employment status, children, mood, physical activity and smoking were analysed.

So were physical factors such as hormone levels, hormone therapy, cholesterol, height, weight, Body Mass Index and blood pressure.

And the study found that, by far, the most powerful driver of good brain health was regular physical activity. Those who remained active for the full period did best. And they didn't have to jog!

"Regular exercise of any type, from walking the dog to mountain climbing, emerged as the No.1 protective factor against memory loss," says Szoeke.

"And we were surprised to find the effect of exercise is cumulative, that is, how much and how often you do over the course of your life adds up."

"If you don't start at 40, you could miss one or two decades of improvement to your cognition because every bit helps. But that said, even once you're 50 you can make up for lost time."

The study showed the next two strongest protective factors were having normal blood pressure and a high level of "good" cholesterol.

The women were drawn from the Women's Healthy Ageing Project for the study funded by the National Health and Medical Research Council and the Alzheimer's Association.

Most studies on cognitive decline recruit people over 60 because the incidence of dementia doubles every five years over 65.

Good for the heart, good for the brain

For the first time, this study looked at what could be done from the age of 45 to improve functioning memory. It looked at all factors and singled out the most powerful, translating that into a simple public health message.

Szoeke, who is director of the Healthy Ageing Program at the University of Melbourne, says although it's widely known physical activity is good for the heart and prevents obesity and diabetes, this study shows it is clearly good for the brain too.

"There's always been some confusion between the risk factors for the heart and the brain. While there is a huge overlap in the factors, the impact of each factor is not the same on both organs and our results show this."

This is best illustrated with "bad" cholesterol. While high levels put the heart at risk, when it comes to dementia, the most important factor was the good "HDL" and the pattern of influence by cholesterol was not the same as that observed for heart disease.

Szoeke says women wanting to protect themselves from dementia usually have to wade through pages of information, listing all the factors that can have an adverse effect, but many of the factors have only been examined independently, without consideration of their interactions.

"The goal of our study was to move towards clear streamlined advice without mixed messages," she says.

"All the factors are inter-related but if you have to pick one, it's physical activity!"

No time like the present

Published in The American Journal of Geriatric Psychiatry, the study took all-comers and considered all forms of physical activity. It found the optimum was daily exercise, seven days a week and it offered no prescription for the intensity or duration of the exercise.

"Start now because if you wait, you will disadvantage your health," Szoeke says.

 "Intervention is better late than never, but an intervention at 65 would have missed at least 20 years of aggregate risk."

Unlike the capacity of muscles and vessels to remodel and reverse wasting and damage, she says nerve cells don't have nearly the same versatility and damage and cell loss can be irreversible.

Source: http://bit.ly/28S5JFS