Many individuals look forward to living to a ripe old age, with the caveat being that they remain in a decent state of health. Ideally, our later years should be vibrant, and not too tinged with signs of physical or mental decay. There are several lifestyle factors that can help ensure healthy ageing, including diet, sleep and sunlight exposure. Another one, of course, is exercise.
Traditionally, exercise has been touted for its benefits for physical health. Regular has been associated with a reduced risk of a variety of conditions including cardiovascular diseases and type 2 diabetes. But health is not just about the body: it’s about the brain too. What, if any, influence does exercise have on brain function?
Well, there is ‘epidemiological’ research which links higher levels of activity with better brain function. The problem with this research (like pretty much all epidemiological research) is that it only tells us that activity and improved brain function are associated. It might not be the case that activity actually boosts or helps preserve brain function. Maybe those who are active eat better and smoke less, and its these factors (not the activity) that have benefits for the brain.
To establish whether exercise does indeed benefit the brain what we really require is ‘intervention’ studies. Studies where individuals are put through some sort of exercise programme while their brain function is assessed.
Such a study was published recently in the journal Frontiers in Aging Neuroscience [1]. In this study, a group of sedentary individuals aged 59 – 80 had their brain function assessed. They were then randomised to one of two exercises regimes:
- walking (at one’s own pace) for 40 minutes, three times a week
- regular stretching and toning exercises
Study subjects were reassessed after 6 and 12 months.
Assessment took more than one form. One test employed was ‘functional magnetic resonance imaging’ (fMRI). This tests brain activity. One part of the brain the researchers were particularly interested in is known as the ‘default mode network’. This part of the brain in most active when individuals are inwardly focused, but becomes naturally more quiet once someone has to focus on their external environment for some reason.
Previous research has shown that fitter individuals have greater ‘connectivity’ in their default mode network, and also tend to be better at a range of mental tasks including planning, prioritising and strategising. This work is epidemiological though, so let’s get back to the intervention study that is our focus here.
At the end of the study (12 months), compared to those who had been stretching and toning, those on the walking regime saw, on average, an increase in the default mode network connectivity. They also saw increased activity in another part of the brain (known as the ‘fronto-executive network’) which assists individuals perform complex tasks.
Crucially, though, the walkers did on a range of cognitive tests too, especially those that are sometimes referred to as ‘executive control tasks’ (e.g. planning, scheduling, dealing with ambiguity and multi-tasking). It is these skills, by the way, that do tend to take a bit of a hit when we age.
What we have here is an intervention study showing that activity in the form of walking, even in later life, has the ability to help enhance brain function, especially in terms of functions that are prone to decay as we age.
For more information on why walking may be the ideal exercise while we age, see here.
References:
1. Voss MW, et al. Plasticity of brain networks in a randomized intervention trial of exercise training in older adults. Frontier in Aging Neuroscience doi: 10.3389/fnagi.2010.00032
What an interesting study. Using MRI in dietary studies would be fascinating too.
A study published in the Journal of the American Medical Association (1) last year found that eating a Mediterranean-style diet was associated with a reduced risk for Alzheimer’s disease. The study also found that physical activity was associated with a reduced risk for Alzheimer’s disease, independent of diet. Adhering to a Mediterranean diet as well as having a good level of physical activity further reduced the risk of developing this disease in this study. Although the study was only observational I found it interesting, especially the apparent protective effect of physical activity against Alzheimer’s disease.
The study used data from 1880 elderly residents, who had an average age of 77, living in New York. None of the participants had Alzheimer’s disease or dementia at the start of the study which ran from 1992 to 2006. Diet and level of physical activity were assessed and scored at the beginning of the study. Physical activity was scored as vigorous (e.g. jogging), moderate (e.g. hiking or cycling) and light (e.g. golfing or gardening). For diet the participants were given a score from 0-9 depending on how close to a Mediterranean diet their diet was. These scores were then grouped into low, middle or high adherence to a Mediterranean diet. Over the course of the study, about every 18 months, participants underwent neurological and neuropsychological tests.
* A total of 282 cases of Alzheimer’s disease were diagnosed over the course of the study.
* The most physically active participants had a 33% reduced risk of developing Alzheimer’s disease when compared to participants who were the least physically active
* Those who most closely followed a Mediterranean diet had a 40% reduction in the risk for Alzheimer’s compared to participants who adhered the least.
* Those who had the highest level of physical activity and whose diet was closest to the Mediterranean diet had a 60% reduced risk of developing Alzheimer’s when compared to those who did not exercise and did not follow a Mediterranean-style diet.
*It was noted that even a low level of physical activity seemed to have a protective effect.
(1)Scarmeas N et al. 2009. Physical Activity, Diet, and Risk of Alzheimer Disease. JAMA. 2009;302(6):627-637.
i find this study to be very sketchy. one group was told to walk while the other was told to do “stretching and toning” activities. i can guarantee that the “stretching and toning” activities were not exactly the same thing as a resistance training program or any real form of exercise. so really all this study tells us is that exercise seems to affect the brain, this does NOT prove that walking is necessarily better than any other form of exercise. my guess is a high-intensity resistance training program would be much more beneficial than low-intensity walking.
Has anyone made a connection with how much one used ones brain before the onset of Alzheimer’s and whether not using ones brain after, say, retirement brought on somekind of dementia? When you think that Winston Churchill, Thatcher and Harold Wilson had jolly good brains but all ended up with some kind of dementia; might it be NOT using ones brain that could also be causative? Like not using ones body allows one to become pretty stiff!
Is there more to a long walk three times a day than just aerobic exercise? Getting out and interacting with the world may be part of the wonder of walking. I’d like to see a treadmill versus real world walking study.
There seems to be some confusion about “dementia” and “Alzheimer’s Disease.” The terms are not interchangeable. More here: http://elderkind.com/walking-off-dementia-exercise-and-the-brain/