Q4's the Winner--that's the group that walked the most! Increased volume in these four brain regions was associated with decreased cognitive impairment. Q4 participants walked the most--6-9 miles a week. Bottom Line: In order to detect any noticeable brain volume changes, participants needed to walk 6-9 miles a week!
"In short, walking greater distances was associated with greater gray matter volume in specific [brain] regions, and greater gray matter volume was associated with a lower risk for experiencing cognitive impairment."
-University of Pittsburgh researchers, "Physical activity predicts gray matter volume in late adulthood" Neurology 75:1415-1422, Oct. 19, 2010-
"The results of this study are exciting in that they suggest an association between physical activity, in the form of walking, brain structure, and dementia across the period of a decade. Such results provide yet another reason for the medical community to prescribe physical activity as a means to reduce the probablilty of age-associated neurodegenerative disease."
-Dr. Arthur Kramer, University of Illinois-Urbana-Champaign-
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Who doesn't want to hold on to every bit of their brain volume as they get older? And if these University of Pittsburgh researchers are right, physical activity may really make a difference. But, forget about walking less than 6 miles a week--it won't do a thing for your brain. You need to kick it up a notch.
Walking at least six miles a week appears to be enough to preserve brain volume, gray matter, and memory, according to a just published University of Pittsburgh study, that appears in, Erickson, KI, et al. "Physical activity predicts gray matter volume in late adulthood: The Cardiovascular Health Study," Neurology. 2010 Oct 19;75(16):1415-22. Epub 2010 Oct 13. Click here
Here it is folks, the first research study to follow a group of seniors for 13 years to find out if physical activity really can preserve cognitive function. You can't argue with MRIs that show it really does take a minimum of 6-9 miles of walking a week to hold on to your brain volume and possibly prevent dementia--both vascular & Alzheimer varieties.
So, go ahead and put on those walking shoes--clip on your pedometer, and aim for at least 6-9 miles a week. That's all they say it will take. Just a mile a day.
"Brain size shrinks in late adulthood, which can cause memory problems. If regular exercise in midlife could improve brain health and improve thinking and memory in later life, it would be one more reason to make regular exercise in people of all ages a public health imperative.
-Dr. Kirk Erickson, one of the study authors-
Walking, Brain Volume, Gray Matter Preservation and Cognitive Impairment
- The study followed 299 dementia-free seniors (mean age of 78) from the Cardiovascular Health Cognition Study, for a period of 13 years. At the start, the participants recorded the number of blocks they typically walked in one week. Range was from 0 to 300 blocks a week.
- Brain volume MRIs. Nine years later the researchers took high-definition brain scans of the participants to measure their brain sizes.
- Cognitive Impairment Testing. Four years after the MRIs were taken, the participants were tested to determine whether they had developed cognitive impairments or dementia.
- 40% of the participants had developed cognitive impairments 13 years later. 116 of the participants (40%) had developed some form of cognitive impairment or dementia 13 years after the study began. This percentage is in line with reported incidences of cognitive impairment.
- Greater gray matter volume decreased cognitive impairment risk 2-fold. The researchers found that those who walked the most cut their risk of memory problems in half.
- Increased brain volume = decreased cognitive impairment. The increased volume in the inferior frontal gyrus, the hippocampal formation, and the supplementary motor area were associated with decreased cognitive impairment.
- 6-9 miles a week is the sweet spot. Those who walked at least 6-9 miles a week had greater gray matter volume, as measured by MRI, than those who didn't. Everyone who walked less than 6 miles a week had similar brain volume loss--making 6-9 miles the minimum threshold of physical activity needed to preserve brain volume.
- It doesn't have to be that hard. More isn't better. Walking over 6-9 miles a week did not appear to increase gray matter volume any further.
But of course, more studies are called for. Too bad they only measured brain volume one time. Too bad the level of physical activity was just self-reported & didn't appear to be followed up regularly. Maybe next time. This study was an observational study based on self-reported activity levels. It needs to be duplicated in larger randomized trials where participants are assigned to specific walking distances and followed for years. "Only under these conditions will we be able to determine the extent to which exercise augments brain function in late life," said Dr. Erickson
Does only walking count? Not at all. The researchers only chose walking because it's the most common form of exercise for older adults, and it doesn't correlate to socioeconomic status like other forms of exercise may, like tennis.
How does exercise improve brain volume? Here's what the authors have to say,
"Our results are in line with data that aerobic activity induces a host of cellular cascades that could conceivably increase gray matter volume.
For example, running enhances learning and promotes the proliferation and survival of new neurons in the hippocampus.
The addition of new cells requires increased nutrients, which are supplied by new vasculature. In a mouse model of Alzheimer's Disease, exercising animals show a reduction in beta-amyloid deposits, reduced tau formatin, and suerior learning rates compared to sedentary animals."
Here's my paraphrase of how Dr. Arthur Kramer explains it:
- How exactly does exercise "pump-up" the brain? (or should I say "plump-up" the brain?) Exercise increases the blood levels of a molecule called IGF-1 (insulin-like growth factor). It usually can't cross the infamous "blood-brain barrier", but magically, it does with exercise.
- The IGF-1 increases the blood flow in the brain, which actually makes the brain produce more neurons and other functional brain cells.
- The part of the brain crucial to forming new memories, the hippocampus (first to shrink with age & stress) is benefited the most by IGF-1. Which means: Exercise is the antidote we need to protect our aging brains!
To read more about the benefits of exercise on the brain, check out the research of the exercise-brain booster maven, Dr. Arthur Kramer of the University of Illinois-Urbana. "Where Did I Leave My Glasses? So How Exactly Is Exercise Going to Help Me Find Them?
Interested in buying a pedometer? Here's what a recent New York Times article about the value of walking, advises: If you are shopping for a pedometer, you may want to consider buying one of the brands that are widely used in pedometer research and have been tested for reliability. They include the Accusplit AE120 and the Yamax Digiwalker SW-200.
Check Out This Video of a REALLY REALLY HEALTHY LIBRARIAN
Thanks to Pam for letting me know what the future may hold if we plan ahead. Click here if you don't see the video.