Strength Training Protects Your Brain Against Dementia
Lifting weights can slow age-related degeneration of the brain, studies suggest
Are you worried about memory loss?
Nearly 50 million people worldwide have dementia and Alzheimer’s disease is the most common degeneration of the brain. In the United States, 5.8 million people are currently living with Alzheimer’s. Experts expect the number to increase to 14 million by 2050.
It is a progressive disease with dementia symptoms worsening over time.
Though there is no cure, a study published in The Lancet indicates that the worldwide prevalence of Alzheimer’s could be cut by 35% if people would make lifestyle choices that protect brain health.
Your brain is a dynamic organ, continually remodelling itself in response to your lifestyle, and exercise is one of those positive lifestyle choices.
While the majority of studies have focused on aerobic exercise for brain health, new research suggests that strength training can have equally powerful effects.
Strong muscles, strong memory
Broadhouse et al. (2020) recruited 100 participants for a study that showed strength training can slow and even halt the degeneration of brain cells vulnerable to Alzheimer’s disease.
All participants were at risk for developing Alzheimer’s due to mild cognitive impairment, but none of the recruits were demented or depressed.
The researchers split the study participants into four groups. One group performed computerized brain training. One strength trained. The third group strength-trained and brain-trained. The fourth group served as the control group. Participants who strength trained completed two strength-training sessions weekly for six months. Each session lasted 45 minutes.
The researchers found significant differences in brain anatomy between the strength training group and the control group.
They could show that strength training slows and even halts the degeneration of the hippocampus and its sub-regions. The hippocampus is the region in the brain associated with memories, and scientists link the shrinking of the hippocampus with the presence of Alzheimer’s disease. The rate of the shrinkage of the hippocampus can predict whether mild cognitive impairment (MCI) progresses to Alzheimer’s or not.
Long-term neuroprotection
Remarkable about this study is that for the first time, researchers were able to show that lifestyle intervention had long-lasting protective benefits.
Twelve months after the strength training has stopped, there was a clear difference in brain anatomy between the exercise group and the other study participants.
While the control group had a shrinking of the Alzheimer-vulnerable brain regions of around 3-4%, the strength training group showed a shrinking of only 1-2% and, in some areas, none at all. Because their findings show a strong protective effect of strength training against Alzheimer’s, the authors conclude that resistance exercise should be an integral part of lifestyle-based prevention measures in older populations.
Exercise frequency matters
One question the researches did not address in this study was how often one should lift weights to reap the brain-protective benefits.
A study published by Bolandzadeh et al. (2015) may provide an answer.
The researchers in this study focused on resistance exercise’s effect on the brain’s white matter, which is the material that connects the different brain regions. Previous research has shown that white matter lesions affect our cognitive abilities and are a risk factor for Alzheimer’s disease.
For this trial, the researchers recruited 54 women who were already part of a brain health study and showed white-matter lesions. All of them had already had at least one brain scan.
The participants were split into three groups. One strength trained once per week and one group strength trained twice per week. The third group served as a control group and followed an exercise regimen of stretching and balance training. All women followed their respective routines for one year.
After that period, their brains were scanned again. What the researchers found is that the women who focused on strength training twice weekly showed significantly less white matter degradation than the control group, which focused only on stretching and balance training.
Interestingly, the women who strength trained once per week showed a progression in the number and size of white matter lesions that were similar to those of the control group.
Both groups also showed a significant slowing of their gaits, whereas the group who strength trained twice per week walked more quickly.
The slowed progression of white matter lesions was significantly associated with gait speed.
This study clearly showed that the neuroprotective impact of pumping iron requires a minimum threshold of exercise.
Once a week is likely not sufficient, but twice a week may already be enough.
The take-home message seems clear: strength train to protect your brain from age-related memory loss.