Vigorous physical activity could reduce the number of Alzheimer’s cases by up to 30 per cent, according to Professor Nicola Lautenschlager at The University of Melbourne. She calls the benefits to be gained from getting some sweat on your brow ‘massive’.
Alzheimer’s disease is a devastating neurodegenerative disorder thought to be triggered by the dangerous accumulation of particular proteins, such as amyloid plaques. It is the leading cause of dementia among the elderly and, in developed countries, the fourth leading cause of death.
While Alzheimer’s is often diagnosed in senior years, a growing understanding of the disease is revealing that the pathological proteins start to build up much sooner. For example, amyloid proteins may begin accumulating in the brain 30 years before clinical symptoms emerge, says Lautenschlager.
Some people find this ‘rather scary’, she says. But to the professor the new research is ‘very exciting information’. It opens up the possibility of preventing further build up of toxic proteins in our healthier years.
‘You can make a difference on the concentration of these pathological proteins just by modifying your lifestyle,’ says Lautenschlager.
People who report doing a lot of physical activity, for example, have a lower risk of dementia and cognitive decline when compared to those who aren’t active. As a minimum, Lautenschlager recommends older Australians do around 150 minutes of physical activity every week
However, when it comes to protecting our noggin, not all exercise is created equal. Aerobic exercise seems to be key. And no slacking off. ‘You have to work up a sweat and you have to have more intensive breathing,’ says Lautenschlager. ‘So it’s not the stroll with a walking buddy where you have a chat or you stop at every corner with your dog.’
‘You have to walk fairly fast, so we call that moderate to vigorous,’ she says, adding that combining aerobic exercise with resistance training, such as weightlifting, may be even more beneficial.
Lautenschlager’s own work has found that a walking regime can even be beneficial for people who are already concerned about their memory or have a diagnosis of mild cognitive impairment. In 2008, she published a pioneering study involving 170 seniors with memory deficits, or concern about this. Half the participants were encouraged to walk for 150 minutes every week, for six months, while a control group wasn’t asked to do any physical activity.
‘What we found was, really to our surprise, how striking the effect was,’ she says. ‘The cognition was clearly much better than in the control group.’ More promising, the benefits had a lasting effect. ‘Even a year later you could still see the effect,’ she says.
However, according to Lautenschlager, not all studies looking into exercise’s effect on cognition show benefits. ‘It’s not consistent,’ she says. ‘So you have negative and positive findings, but we have increasingly more often publications which show that regular physical activity can improve cognition.’
For example, a review paper published last year in the Annual Review of Psychology concluded that, overall, there was ‘consistent’ evidence that physical activity—particularly moderate intensity exercise—improves the ‘cognitive vitality’ of older adults. However, the authors noted that when it came to protecting adults who already had mild cognitive impairment the evidence for a benefit was weaker. Most studies on this had been plagued with small sample sizes, they noted, calling for further work in the area.
Similarly, the review concluded that although there are ‘promising results’ from exercise trials in people diagnosed with Alzheimer’s disease ‘more research is needed before we can conclude that exercise is protective for age-related neurological diseases’.
Another puzzle is how a bit of huffing and puffing might protect cognition, or potentially slow down the accumulation of toxic proteins in your brain.
‘It’s probably very complex,’ says Lautenschlager. ‘But it looks like you have direct effects on the brain.’ For example, exercise may trigger the production of particular proteins that encourage nerves to grow, leading to more connections between nerve cells.
Exercise may also have indirect benefits to our brain, perhaps, through our heart. By reducing high blood pressure and increasing blood flow to the brain, Lautenschlager says vigorous physical activity may protect our cognitive capacity.
There is even the possibility that the positive psychological effects of exercise and social interaction are somehow helping to stave off dementia.
Meanwhile, another lifestyle factor—a healthy diet—is increasingly being viewed as important for reducing the risk of dementia.
Lautenschlager says eating well is ‘extremely important’ to protect our aging brains. Why this is so?
She says that compared to the conundrum of how exercise staves off dementia, we know even less about how diets wield their magic on our mind.