Keeping a healthy brain - what type of exercise is best?
We know that exercise is good for the brain. However most of the research has been focussed on the effects of energetic aerobic activities on brain health. New research by Dr. Teresa Liu-Ambrose, at University of British Columbia, suggests that light resistance training might be effective at slowing the age-related shrinking of some parts of our brains.
It is normal for brains to change constantly and accumulate lesions
Our brains are, of course, dynamic organs, adding and shedding neurons and connections throughout our lifetimes, remodelling and repairing in response to our lifestyle. Similar to the rest of our body, the brain is vulnerable to changes that accumulate over time. Many brain studies have found that, by late middle age, most of us have begun developing age-related holes or “lesions” in our brain’s white matter. The white matter is the material that connects and passes messages among different brain regions. But what do these lesions mean?
What do these lesions mean?
These holes are usually often unnoticeable at first; they show up on brain scans long before someone notices any changes in memory or thinking skills. As the holes widen and multiply over time, the loss of white matter may affect our thinking. Research on this topic indicates that older people with many lesions tended to have worse cognitive abilities than those whose white matter is relatively intact (fewer lesions).
Can weight training exercises reduce the accumulation of lesions?
Dr. Liu-Ambrose and her colleagues turned to a large group of generally healthy women, ages 65 to 75, already enrolled in a brain-health study. The women had already had at least one brain scan. For this study, they zeroed in on 54 of the women, whose scans showed existing white matter lesions. They collected initial information on the women’s gait speed and stability,randomly assigned them to one of three groups and sent them off to exercise for one year. At the end of the year, their brains were scanned again and their walking ability reassessed.
- Group 1 - Once-weekly weight training – supervised, light upper- and lower-body weight training
- Group 2 – Twice-weekly weight training – supervised, light upper- and lower-body weight-training
- Group 3 - Twice-weekly stretching and balance training
The results were sobering and stirring. The Twice-weekly stretching and balance training women (Group 3) showed worrying progression in the number and size of the lesions in their white matter and in the slowing of their gaits.
So did the Once-weekly weight training women (Group 1).
But Group 2 – Twice-weekly weight training - showed significantly less shrinkage and fewer lesions in their white matter than the other women. Their lesions had grown and multiplied somewhat, but not nearly as much. These women could also walk more quickly and smoothly than the women in the other two groups.
These findings suggest that weight training can beneficially change the structure of the brain, but that “a minimum threshold of exercise needs to be achieved,” Prof. Liu-Ambrose said.
What can you do?
Include a visit to the gym to perform weight training at least twice a week, in addition to your other regular exercise. Once a week is probably insufficient.
Does the improvement extend to ability to think?
This study did not closely examine whether differences in the women’s white matter translated into meaningful differences in their ability to think, although Prof. Liu-Ambrose and her colleagues hope to study that issue soon, as well as whether men’s brains respond similarly to weight training.
What is happening in the white matter?
Dr. Liu-Ambrose hopes to learn more about just how weight training affects white matter. It may be that strengthened muscles release substances that migrate to the brain and stimulate beneficial changes there. Or that weight training, in improving walking ability, might affect portions of the brain related to movement that in turn somehow slow the brain’s loss of white matter.
Take home message?
Whatever the reason, regular exercise that includes twice weekly weight training clearly “has benefit for the brain,” Prof. Liu-Ambrose said.
“…..we are just really now gaining an appreciation for how impactful exercise can be.”