Exercise to Reclaim Some of Your Aging, Shrinking Brain

senior cardioI read this yesterday:

Aerobic exercise, such as running, has positive effects on brain structure and function, for example, the generation of neurons (neurogenesis) in the hippocampus, a brain structure important in learning. It has been unclear whether high-intensity interval training (HIT), referring to alternating short bouts of very intense anaerobic exercise with recovery periods, or anaerobic resistance training has similar effects on hippocampal neurogenesis in adulthood. In addition, individual genetic variation in the overall response to physical exercise likely plays a part in the effects of exercise on adult neurogenesis but is less studied.

-from “Adult Neurogenesis May Be Increased by Sustained Aerobic Exercise”

However, this wasn’t established to be true for human beings but rather for adult male rats in a study conducted by researchers from the Department of Psychology and from the Department of Biology of Physical Activity at the University of Jyväskylä. Three groups of rats were studied over a 6 to 8 week program: rats with a genetically high response to aerobic training (HRT), those with a low response to aerobic training (LRT), and a control group that remained in sedentary conditions in the home cage.

And the results?

Compared to sedentary animals, HRT rats that ran voluntarily on a running wheel had 2-3 times more new hippocampal neurons at the end of the experiment. Resistance training had no such effect. Also the effects of HIT were minor.

So if you’re an adult male rat, and particularly a rat that has a “genetic predisposition to benefit from aerobic exercise,” aerobic training will improve hippocampal neurogenesis.

rat cardio wheel
Photo: pamowensfitness.com

What that means is that said-rats have the preconditions for improved learning. It’s suggested in the last sentence of this article that these results might be generalized to humans, but I’m dubious.

Oh, I’m not saying it couldn’t happen. I’m just saying that a rat is not a human being, so I’d need to have more evidence before I start trying to figure out how to work more cardio into my exercise schedule.

But that isn’t the end of the story.

A long time ago, Scotland surveyed the intelligence of every Scottish child that had been born in 1936. More recently, 691 of those former children celebrated their 70th birthdays by filling out a survey about their social and intellectual pursuits and their levels of physical activity. Three years after that, they celebrated their 73rd birthdays by undergoing brain MRI scans at the University of Edinburgh in Scotland. The researchers assessed the brain images for physical signs of cognitive decline.

by Stefan Wermuth/Reuters
-from “Study: People Who Exercise Have Larger Brains Later in Life”
The Atlantic

The results were that physical activity was positively “associated with larger gray and normal-appearing white matter volumes, less atrophy, and fewer white matter ‘lesions.'” Both men and women who exercised experienced less brain shrinkage and fewer structural changes that indicate cognitive decline.

The conclusion was that exercise can be considered as a “neuroprotective factor.” Unfortunately, there was no breakdown as to different kinds of exercise, how frequent, how intense, so that’s as far as we can take it. Some form of physical exercise (as opposed to relaxation or mental exercises such as doing crossword puzzles and such) somehow slows age-related brain degradation.

However, I did locate another article from a few years back at Forbes.com written by David DiSalvo called “How Exercise Makes Your Brain Grow,” that seemed to mirror the NeuroscienceNews.com report.

Research into “neurogenesis”—the ability of certain brain areas to grow new brain cells—has recently taken an exciting turn. Not only has research discovered that we can foster new brain cell growth through exercise, but it may eventually be possible to “bottle” that benefit in prescription medication.

Image: learning-mind.com

I did appreciate this writer confirming that the hippocampus is a “brain area closely linked to learning and memory,” and that it “is especially receptive to new neuron growth in response to endurance exercise.”

The article further states that:

Research has discovered that exercise stimulates the production of a protein called FNDC5 that is released into the bloodstream while we’re breaking a sweat. Over time, FNDC5 stimulates the production of another protein in the brain called Brain Derived Neurotrophic Factor (BDNF), which in turns stimulates the growth of new nerves and synapses – the connection points between nerves – and also preserves the survival of existing brain cells.

Not good news for weight and strength training “gym rats,” but runners have got to love it. But again, this is based on animal studies, so we don’t have conclusive evidence this happens with human beings as well.

However, if it does work on people, apparently it’s possible to put this protein in a pill, which means you don’t have to run, you just have to swallow (and be able to afford the price tag of whatever Big Pharma is going to put on this drug) to head off the effects of Alzheimer’s, Parkinson’s, and other knowledge and memory stealing cognitive disorders.

All we’ve got right now is that there’s a big maybe of a chance that people might benefit cognitively as well as physically from regular cardio exercise. OK, it’s probably worth a shot.

Photo: knightnews.com

And according to the National Institutes of Health:

Ageing causes changes to the brain size, vasculature, and cognition. The brain shrinks with increasing age and there are changes at all levels from molecules to morphology. Incidence of stroke, white matter lesions, and dementia also rise with age, as does level of memory impairment and there are changes in levels of neurotransmitters and hormones. Protective factors that reduce cardiovascular risk, namely regular exercise, a healthy diet, and low to moderate alcohol intake, seem to aid the ageing brain as does increased cognitive effort in the form of education or occupational attainment. A healthy life both physically and mentally may be the best defence against the changes of an ageing brain. Additional measures to prevent cardiovascular disease may also be important.

So this may be especially (potentially) important news to we older folks.

However, in addition to aging, Time Magazine says there are four other factors that contribute to your brain shrinking:

  • High blood pressure
  • Diabetes
  • Cigarette smoking
  • Being overweight or obese

In other words, what most people would consider “unhealthy lifestyle” factors.

By the way, these conclusions were the result of the Framingham Offspring Cohort Study of “1,352 adults who had an average age of 54 and did not have dementia at the start of the study,” so at least human beings were involved and not rats.

On top of this, an article called “The Things That May Shrink Your Brain” published about 5 years ago at The Atlantic Wire listed further possible causes of brain shrinkage.

Alcohol was on the list, but wine was a bigger offender than beer (good news for beer lovers), sleeplessness (what a bummer), lack of sunlight (break out those sunlamps), and “Internet addiction” (dial down the web surfing).

You can read the entire article, but for at least some of these, the evidence is pretty thin.

Additional information can be found at the National Institute on Aging.

Rose McIver as Olivia ‘Liv’ Moore on the television show “iZombie”

So in general, the bad news is that, no matter what, our brains shrink at least somewhat as we age (I guess that means we’re safer from zombies because we don’t provide much of a meal). The good news is that it looks like we can do some things to slow this down and protect ourselves from neurological damage that might lead to serious cognitive decline.

Part of that is eating right (so lay off the Big Macs and KFC) and exercise, probably just cardio exercise.

Wish they’d dream up a study that concluded lifting heavy weights pumped up brains as well as brawn.

You are right to be wary. There is much bullshit. Be wary of me too, because I may be wrong. Make up your own mind after you evaluate all the evidence and the logic.

Mark Rippetoe


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