Researchers have found that six months of strength training (lifting weights) can help protect brain areas especially vulnerable to Alzheimer’s disease up to one year later.
The team, led by researchers at the University of Sydney, conducted a clinical trial for older people at high risk of Alzheimer’s disease due to mild cognitive impairment.
Mild cognitive impairment involves a decline in memory and other thinking skills, despite generally intact daily living skills, and is one of strongest risk factors for dementia. People with mild cognitive impairment are at a one-in-10 risk of developing dementia within a year.
Study participants were randomly allocated to do computerised brain training, strength training, combined computer and strength training, which they did for just six months followed by their usual activity for 12 months.
The long-term study found that strength training led to overall benefits to cognitive performance, benefits linked to protection from degeneration in specific subregions of the hippocampus. The hippocampus is a complex structure in the brain with a leading role in learning and memory.
The hippocampus subregions targeted by the strength training were those especially vulnerable to Alzheimer’s disease.
In the control group, where no strength training was undertaken, hippocampal subregions shrank by three to four per cent over the 18 months, while for those undergoing strength training the reduction was just one to two per cent and, in some areas, none at all.
Strength training is a type of physical exercise that requires repetitive contraction of the main muscle groups against an opposing force, typically a free weight or using gym equipment. Participants in this study did supervised strength training for just 90 minutes in total each week, over two or three weekly sessions.
Dr Kathryn Broadhouse, now with the University of the Sunshine Coast, who led the analysis while at the University of Sydney, said the data showed that strength training could exert important biological effects.
“Our research shows that strength training can protect some hippocampal subregions from degeneration or shrinkage for up to 12 months after the training has stopped,” Dr Broadhouse said.
To arrive at their conclusions, the team conducted MRI brain scans of the participants three times over an 18-month period and used some of the latest advances in image analysis to quantify changes to subregions within the hippocampus, the brain’s memory hub.
“Hippocampal segmentation is difficult because the borders between structures are sometimes unclear and even anatomists will debate where to draw the line, so we restricted our analysis to those subregions where the data is consistent,” Dr Broadhouse said.
Professor Michael Valenzuela, leader of the Regenerative Neuroscience Group at the University of Sydney’s Brain and Mind Centre and the senior author of the study, believes the finding should change the dementia prevention message.
“This is the first time any intervention, medical or lifestyle, has been able to slow and even halt degeneration in brain areas particularly vulnerable to Alzheimer’s disease over such a long time,” said Prof. Valenzuela.
“Given this was also linked to protection from cognitive decline, the message is clear: resistance exercise needs to become a standard part of dementia risk-reduction strategies,” he said.
Prof. Valenzuela is one of the leaders of the multimillion-dollar Australian Maintain your Brain online trial (www.maintainyourbrain.org) that will test if a tailored program of lifestyle modification, including resistance exercise, can prevent cognitive loss in a group of 6000-plus older adults.
Do you do any strength training as part of your regular exercise regimen?
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