For years, scientists have known that moving our bodies can sharpen our minds. Physical activity boosts blood flow to the brain, enhances neuroplasticity and reduces chronic inflammation. These processes are believed to protect against cognitive decline, including dementia.

Yet despite decades of research, major questions have remained unresolved.

Does exercising at any age help reduce your risk of dementia? Or only when you’re young? And what if you have a higher genetic risk – can exercising still make a difference?

New research from the long-running Framingham Heart Study in the United States, published today, offers some of the clearest answers to date. Their findings support what many clinicians already tell patients: exercise helps.

But the study also offers new insight into the potentially protective effect of staying active at the age of 45 and over – even for those with a certain genetic predisposition to dementia.

What did the study examine?

The new research draws on data from 4,290 participants enrolled in the Framingham Heart Study Offspring cohort. This study began in 1948, when researchers recruited more than 5,000 adults aged 30 and over from the town of Framingham, Massachusetts, to investigate long-term risk factors for cardiovascular disease.

In 1971, a second generation (more than 5,000 adult children of the original cohort, and their spouses) were enrolled, forming the Offspring cohort. This generation then had regular health and medical assessments every four to eight years.

In the new study, participants self-reported their physical activity. This included incidental activity such as climbing stairs as well as vigorous exercise.

Participants first reported these activities in 1971, and then again over several decades. Based on the age at which each participant was first evaluated, they were grouped into three categories:

• young adulthood (26–44 years): assessed in the late 1970s
• midlife (45–64 years): assessed during the late 1980s and 1990s
• older adulthood (65 years and over): assessed in the late 1990s and early 2000s.

To examine how physical activity influences dementia risk, the researchers looked at how many people developed dementia in each age group and at what age they were diagnosed.

Then they considered physical activity patterns within age groups (low, moderate, high) to see if there was any link between how much exercise people did and whether they developed dementia.

They also looked at who had a known genetic risk factor for Alzheimer’s disease, the APOE ε4 allele.

What did they find?

Over the follow-up period, 13.2% (567) of the 4,290 participants developed dementia, mostly in the older age group.

This is quite high compared with other long-term longitudinal dementia studies and with Australian rates (one in 12 or 8.3% Australians over 65 currently have dementia).

When researchers examined physical activity levels, the pattern was striking. Those with the highest levels of activity in midlife and later life were 41–45% less likely to develop dementia than those who had the lowest levels of activity.

This was the case even after adjusting for demographic factors that increase dementia risk (such as age and education) and other chronic health factors (such as high blood pressure and diabetes).

Interestingly, being physically active during early adulthood did not influence dementia risk.

A key innovation of this study was its examination of the genetic risk factor, the APOE ε4 allele. This analysis suggests something new:

• in midlife, higher physical activity lowered dementia risk only in people who didn’t carry this genetic predisposition
• but in later life, higher physical activity lowered dementia risk in both carriers and non-carriers.

This means for people genetically predisposed to dementia, staying active later in life may still offer meaningful protection.

How significant are these results?

The findings largely reinforce what scientists already know: exercise is good for the brain.

What sets this study apart is its large sample, multi-decade follow-up, and its genetic analysis across different life periods.

The suggestion that midlife activity benefits some individuals differently depending on their genetic risk, while late-life activity benefits nearly everyone, may also add a new layer to public health messaging.

But there were some limitations

Physical activity was largely self-reported in this study, so there is a possibility of recall bias. We also do not know what type of exercise brings the best benefits.

Dementia cases in the youngest age group were rather rare too, so the small sample limits how definitively we can make conclusions about early adulthood.

The cohort is also predominantly of European ancestry and share environmental factors as they come from the same town, so this limits how much we can generalise the findings to more diverse populations.

This is particularly important given global inequities in dementia risk and diagnosis. Knowledge about dementia and risk factors also remains low in ethnically diverse groups, where it is often still seen as a “normal” part of ageing.

What does this mean for us?

The takeaway is refreshingly simple though: move more, at any age. At this stage we know there are more benefits than harm.

Joyce Siette, Associate Professor | Deputy Director, The MARCS Institute for Brain, Behaviour and Development, Western Sydney University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Dementia is the second leading cause of death for Australians aged over 65. More than 421,000 Australians currently live with dementia and this figure is expected to almost double in the next 30 years.

There is ongoing public discussion about whether dementia should be a qualifying illness under Australian voluntary assisted dying laws. Voluntary assisted dying is now lawful in all six states, but is not available for a person living with dementia.

The Australian Capital Territory has begun debating its voluntary assisted dying bill in parliament but the government has ruled out access for dementia. Its view is that a person should retain decision-making capacity throughout the process. But the bill includes a requirement to revisit the issue in three years.

The Northern Territory is also considering reform and has invited views on access to voluntary assisted dying for dementia.

Several public figures have also entered the debate. Most recently, former Australian Chief Scientist, Ian Chubb, called for the law to be widened to allow access.

Others argue permitting voluntary assisted dying for dementia would present unacceptable risks to this vulnerable group.

Australian laws exclude access for dementia

Current Australian voluntary assisted dying laws exclude access for people who seek to qualify because they have dementia.

In New South Wales, the law specifically states this.

In the other states, this occurs through a combination of the eligibility criteria: a person whose dementia is so advanced that they are likely to die within the 12 month timeframe would be highly unlikely to retain the necessary decision-making capacity to request voluntary assisted dying.

This does not mean people who have dementia cannot access voluntary assisted dying if they also have a terminal illness. For example, a person who retains decision-making capacity in the early stages of Alzheimer’s disease with terminal cancer may access voluntary assisted dying.

What happens internationally?

Voluntary assisted dying laws in some other countries allow access for people living with dementia.

One mechanism, used in the Netherlands, is through advance directives or advance requests. This means a person can specify in advance the conditions under which they would want to have voluntary assisted dying when they no longer have decision-making capacity. This approach depends on the person’s family identifying when those conditions have been satisfied, generally in consultation with the person’s doctor.

Another approach to accessing voluntary assisted dying is to allow a person with dementia to choose to access it while they still have capacity. This involves regularly assessing capacity so that just before the person is predicted to lose the ability to make a decision about voluntary assisted dying, they can seek assistance to die. In Canada, this has been referred to as the “ten minutes to midnight” approach.

But these approaches have challenges

International experience reveals these approaches have limitations. For advance directives, it can be difficult to specify the conditions for activating the advance directive accurately. It also requires a family member to initiate this with the doctor. Evidence also shows doctors are reluctant to act on advance directives.

Particularly challenging are scenarios where a person with dementia who requested voluntary assisted dying in an advance directive later appears happy and content, or no longer expresses a desire to access voluntary assisted dying.

Allowing access for people with dementia who retain decision-making capacity also has practical problems. Despite regular assessments, a person may lose capacity in between them, meaning they miss the window before midnight to choose voluntary assisted dying. These capacity assessments can also be very complex.

Also, under this approach, a person is required to make such a decision at an early stage in their illness and may lose years of otherwise enjoyable life.

Some also argue that regardless of the approach taken, allowing access to voluntary assisted dying would involve unacceptable risks to a vulnerable group.

More thought is needed before changing our laws

There is public demand to allow access to voluntary assisted dying for dementia in Australia. The mandatory reviews of voluntary assisted dying legislation present an opportunity to consider such reform. These reviews generally happen after three to five years, and in some states they will occur regularly.

The scope of these reviews can vary and sometimes governments may not wish to consider changes to the legislation. But the Queensland review “must include a review of the eligibility criteria”. And the ACT bill requires the review to consider “advanced care planning”.

Both reviews would require consideration of who is able to access voluntary assisted dying, which opens the door for people living with dementia. This is particularly so for the ACT review, as advance care planning means allowing people to request voluntary assisted dying in the future when they have lost capacity.

This is a complex issue, and more thinking is needed about whether this public desire for voluntary assisted dying for dementia should be implemented. And, if so, how the practice could occur safely, and in a way that is acceptable to the health professionals who will be asked to provide it.

This will require a careful review of existing international models and their practical implementation as well as what would be feasible and appropriate in Australia.

Any future law reform should be evidence-based and draw on the views of people living with dementia, their family caregivers, and the health professionals who would be relied on to support these decisions.

Ben White, Professor of End-of-Life Law and Regulation, Australian Centre for Health Law Research, Queensland University of Technology; Casey Haining, Research Fellow, Australian Centre for Health Law Research, Queensland University of Technology; Lindy Willmott, Professor of Law, Australian Centre for Health Law Research, Queensland University of Technology, Queensland University of Technology, and Rachel Feeney, Postdoctoral research fellow, Queensland University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.