A report published Sunday by the National Academies of Sciences, Engineering, and Medicine (NASEM) said there is evidence, although "inconclusive," to support that increased physical exercise, controlling blood pressure and some form of cognitive brain training might reduce mental decline in old age and prevent cognitive decline and dementia.

"Cognitive training, blood pressure management for people with hypertension, and increased physical activity all show modest but inconclusive evidence that they can help prevent cognitive decline and dementia, but there is insufficient evidence to support a public health campaign encouraging their adoption," the report stated.

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The report also noted that additional research will be required to understand and analyze the effectiveness of these three interventions for brain health.

"There is good cause for hope that in the next several years much more will be known about how to prevent cognitive decline and dementia, as more clinical trial results become available and more evidence emerges," said Alan I. Leshner, chair of the committee and CEO emeritus, American Association for the Advancement of Science.

"The evidence is strong enough to suggest the public should at least have access to these results to help inform their decisions about how they can invest their time and resources to maintain brain health with ageing," Leshner explained.

The NASEM report came to a conclusion based on available evidence, that the three interventions were supported by "encouraging but inconclusive" evidence. According to the report, the interventions are:

1. Cognitive training, which includes programs "aimed at enhancing reasoning and problem solving, memory, and speed of processing, to delay or slow age-related cognitive decline. May or may not be computer-based."

2. Blood pressure management for people with hypertension, particularly during midlife, generally aging from 35 to 65 years, "to prevent, delay, and slow clinical Alzheimer's-type dementia."

3. Increased physical activity, which is used to "delay or slow age-related cognitive decline."

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Managing vascular health has been critical for brain health, according to Maree McCabe, Alzheimer's Australia chief executive officer, who said: "We know what's good for your heart is good for your brain and having a healthy vascular system certainly reduces the risk of vascular dementia."

McCabe claimed that there is also proof to show increased physical exercise can lead to a higher volume of the hippocampus, which is that part of the brain where Alzheimer's disease begins to grow.

"If you've got more volume in that area then people if they get Alzheimer's disease will be slower to show clinical symptoms because there is more volume that the disease has got to get through," McCabe was quoted as saying by the Australian Associated Press.

McCabe added: "If we could just reduce the incidence of dementia by just five per cent per year we would reduce the number of people who get it by 24 per cent and that would save the economy $120 billion dollars by 2056, not to mention ensure people have much happier and healthier lifestyles."

An earlier systematic 2010 review published by the Agency for Healthcare Research and Quality (AHRQ) discovered that there was no sufficient evidence to "provide an indication of the effectiveness of increased physical activity in delaying or slowing age-related cognitive decline." The study was sponsored by the National Institute on Aging. Since then, there have been other studies conducted to garner enough evidence. Even the limitation indicated the need for further research and methodological advancements in the future.