The Many Benefits of Exercise (Surprise, Surprise)

By catalyst

I’ve become a big fan of Tara Parker-Pope’s Well blog on health for the New York Times. She highlights some fascinating research, and I find that her Phys Ed sub-blog sheds a floodlight on how our bodies react to exercise—burnishing the shadows popularly held beliefs that can encourage behaviors that have a negative net health effect.

Case in point, this article, which points to a studies[1] [2] showing that running, contrary to popular belief, does not cause degeneration of the cartilage of the kneecaps and thus painful, often debilitating osteoarthritis.

From the blog:

Recent evidence suggests that running may actually shield somewhat against arthritis, in part because the knee develops a kind of motion groove. A group of engineers and doctors at Stanford published a study in the February issue of The Journal of Bone and Joint Surgery that showed that by moving and loading your knee joint, as you do when walking or running, you “condition” your cartilage to the load. It grows accustomed to those particular movements. You can run for miles, decades, a lifetime, without harming it. But if this exquisite balance is disturbed, usually by an injury, the loading mechanisms shift, the moving parts of the knee are no longer in their accustomed alignment and a “degenerative pathway” seems to open. The cartilage, like an unbalanced tire, wears away. Pain, tissue disintegration and, eventually, arthritis can follow.

Parker-Hope quotes a Stanford researcher who says that knee-specific exercises that strengthen the principal running muscles—namely the hip stabilizers, quads, hamstrings and core—can help avoid injuries because “the best way to ensure that your knees aren’t hurt by running is not to hurt them in the first place.”

The blog includes a video showing some simple exercises you can do to make your knees more stable. As an avid runner myself, I’d also recommend basic stationary squats, without any weight. Make sure your kneecaps never break an imaginary plane that extends up from about mid-foot. Tai chi knee rotations are another great way to strengthen knees.

Run for your life – and your sanity

On a recent visit to the Berkeley Graduate School of Journalism, I sat in on a lecture by freelance journalist and This American Life contributor Jack Hitt. He detailed the soul-bleaching, atomic-grade stress many freelance journalists experience. When asked how he coped, he replied, “Eat well and get lots of exercise.” Many people preach the stress-reducing effects of exercise, and according to another Well article by Parker-Pope, there’s mounting evidence that they’re not just whistling Dixie.

It’s well known that exercise grows new brain cells[1] [2], and researchers at Princeton University studying the brains of rats that exercise have discovered that the neurons generated by exercise respond differently to stress than the neurons of slothful rats.

The Princeton researchers let one group of rats run in a hamster wheel and restricted another group to a sedentary life. Then they made the rats swim in cold water, which they apparently don’t like to do. Upon examining the animals’ brains following their polar bear swim, researchers found that the youngest neurons in the gym-rat rats’ brains, which were probably created by running, appeared to be buffered from stress. In effect, “The rats had created, through running, a brain that seemed biochemically, molecularly, calm,” says Parker-Pope.

But does a rat swimming in cold water experience stress levels analogous to those in everyday human life? How similar is their chilly dip to a semi tailgating you as you’re driving home after receiving a pink slip at your job of 15 years and so you’re wondering how on earth you’re going to pay for your depressed son’s Zoloft refills, the voice on the radio’s detailing yet another humanitarian disaster, and then you notice you’re running on “E”? The only rodent equivalent I can imagine is an extended dunk in Arctic salt water. That might cut it.

Other studies, such as those done at the University of Colorado, Boulder, and the University of Houston, have shown that exercise reduces stress on chemical and cellular levels. It seems that exercise is an antioxidant, protecting the body from harmful free radicals, and can mitigate the negative effects of serotonin on the brain.

“It looks more and more like the positive stress of exercise prepares cells and structures and pathways within the brain so that they’re more equipped to handle stress in other forms,” says Michael Hopkins, a graduate student affiliated with the Neurobiology of Learning and Memory Laboratory at Dartmouth, who has been studying how exercise differently affects thinking and emotion. “It’s pretty amazing, really, that you can get this translation from the realm of purely physical stresses to the realm of psychological stressors.”

Parker-Pope quotes a researcher from the University of Colorado, Benjamin Greenwood, who says that it’s not clear how the info gleaned from the rat studies translates into prescriptions for human exercise. Nonetheless, Parker-Pope says, virtually every researcher agrees that you won’t enjoy the stress-reducing benefits of exercise if the most you do is run around the block every other Tuesday evening. It could takes three, six or even more weeks of steady exercise to grow enough young, stress-buffered neurons to reduce general anxiety.

Exercise could help you lose more than unwanted poundage

But there could be a drawback to all those new neurons generated by exercise. An article on reports:

The hippocampus is one of only two places in the adult brain where scientists know that new neurons form. A new rodent study shows that newborn neurons destabilize established connections among existing brain cells in the hippocampus, a part of the brain involved in learning and memory. Clearing old memories from the hippocampus makes way for new learning, researchers from Japan suggest in the November 13 Cell… On the basis of previous studies, many researchers think new neurons stabilize memory circuits or are somehow otherwise necessary to form new memories…The new study suggests the opposite: Newborn neurons weaken or disrupt connections that encode old memories in the hippocampus.

In a study done at the University of Yokohama in Japan, researchers learned that rodents who ran in a hamster wheel, and thus grew more young neurons, lost old memories at an increased rate. Which might even be helpful if we could pick and choose which memories were wiped, a la “Eternal Sunshine of the Spotless Mind”.

And while we’re talking about memory, it’s come to my attention that too few people have ever heard of a simply fantastic radio show called Radiolab, produced in New York by NPR affiliate WNYC. Even their motto exudes nerd-cool: “On a curiosity bender.” And here’s their mission statement:

Radiolab believes your ears are a portal to another world.[sic] Where sound illuminates ideas, and the boundaries blur between science, philosophy, and human experience. Big questions are investigated, tinkered with, and encouraged to grow. Bring your curiosity, and we’ll feed it with possibility.

Their shtick is to take a basically unavoidable fact of human life—memory, death, sleep, language—and examine it by asking very basic questions, telling fascinating stories and talking with experts who are conducting ground-breaking research. All of this is delivered in a sonic package that brings the ideas and concepts to life in your ears.

The connection here is that a few years back, Radiolab produced a show about Memory and Forgetting that examines the neurological wiring and fireworks that allow memory and forgetting to happen.

And to follow the thread even further, there’s a growing debate over the value of forgetting in the digital age, when our memories, thoughts and words are preserved on Facebook, MySpace, Twitter and a host of other Web platforms, and the technical innovation that makes it possible for everything you ever experience in your life to be catalogued and stored.

The opposing sides of this debate are captured in either of two new books. Delete: The Virtue of Forgetting in the Digital Age by Viktor Mayer-Schönberg, an Associate Professor at the National University of Singapore, who’s research focuses on the role of information in the digital age. As you’ve probably gathered from the title, Mayer-Schönberg argues for the inherent value of losing memories and facts over time, especially when that information is unfairly used to discriminate. He makes a case for forgetting in this interview with Spark, a production of the Canadian Broadcasting Company.

Gordon Bell, on the other hand, a computer scientist, has offered himself as a guinea pig for Microsoft’s MyLifeBits research project, which aims to enable humans to possess total recall. Total Recall is in fact the name of Bell’s new book, co-written by Jim Gemmell, which claims that, thanks to cyberspace, we need never again worry about forgetting.

But by no means do you want to forget to check back in next week for more info to exercise your mind grapes.

*AUTHORIAL PENITENCE: It’s been about a month since I’ve updated this blog, so my apologies for the extended delay.*

This article was originally published on December 6, 2009.