What is good for the heart is good for the brain. Exercise can have a beneficial effect at any age to help protect against dementia. To help reduce the risk at least 30 minutes of exercise, five times a week is suggested. It does not have to be the gym – a brisk walk is a perfectly acceptable alternative. Whatever form of exercise gets your heart pumping and leaves you somewhat out of breath is doing the trick. Exercise helps maintain a healthy weight and blood pressure, and so is indirectly thought to reduce the risk of dementia.

Being seriously overweight is deemed a risk factor for developing dementia. This really matters in mid-life – between the ages of 35 and 65. Obesity increases the likelihood of developing Type 2 diabetes – believed to be a risk factor – but whether this causes the disease, or is simply more likely to develop in those who are also more prone to dementia is unclear. Obesity is also associated with higher cholesterol and blood pressure – again, known to be risk factors.

Again, the key here is having consistently raised blood pressure in mid-life – anything above 140/90mmHg. It is thought that this increases the chance of dementia by causing damage to the brain.  This may happen as a result of a stroke – in which blood supply to part or all of the brain is cut off – or due to microvascular disease, a condition which slows the flow of blood through the body thereby damaging cells and nerves in the brain.

It is mid-life levels once more which appear to pose the greatest problem. Like high blood pressure, high levels of cholesterol raise the risk of stroke and microvascular disease. But cholesterol is also thought to be involved in the mechanism which causes amyloid protein plaques – the protein deposits that characterise Alzheimer's disease – to build up.

DON'T SMOKE

This had been an area of confusion, as some studies had suggested nicotine could have a protective effect – with the chemical reducing plaques when administered to animals in water. But the way in which we smoke tobacco, and the other chemicals inhaled in the process, negates this benefit. As well as raising the risk of vascular disease – a risk factor for dementia – smoking can result in low oxygen levels in the brain which in turn can promote the production of the protein found in brain plaques.

EAT A MEDITERRANEAN DIET
Several recent studies have highlighted the potential for this diet to reduce the risk of Alzheimer's Disease. It involves eating lots of fruit and vegetables, whole grain foods, fish and plenty of olive oil, but it is relatively low in dairy products and processed foods.

Some evidence suggests that an active social life throughout life can be protective, with both the social ties one enjoys with others and non-physical leisure time deemed important.  One particular study has found that being single and living alone is a risk factor for dementia: social isolation is thought to have negative effects on health generally, increasing depression and cardiovascular disease.

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