playthink

From researchers at Princeton University: Running by yourself could be bad for your brain. Or at least, not as good as running with a group.

According to an article in the journal Nature Neuroscience, as reported by the BBC, exercise can have “negative effects on activity in the brain… Running is known to increase levels of stress hormone corticosterone, which can reduce the creation of new brain cells - a process known as neurogenesis.”

But wait, right?! Isn’t exercise good for the brain? Doesn’t physical activity promote neurogenesis?

Here’s where things can get a bit complicated.

Yes, exercise “has been found to increase spatial awareness and to boost communication between neurons.”

But… Only (or at least, especially) if exercise is done with others. Or if done for a really long time. Here’s the rundown on this study (no pun intended):

The researchers at Princeton looked at rats that ran in groups and rats that ran in social isolation. In both groups, “running caused similar elevations of the stress hormone, which can impair neuron generation.”

However, “running was found to increase neuron generation when rats were housed in groups. In rats that ran in social isolation, neurogenesis was suppressed.”

So even though running increased stress on the brain, which can impair neuron generation, group running “increase[d] spatial awareness and boost[ed] communication between neurons.” Running is stressful for the brain, but the social aspect of group running produced more good things for the brain than it hurts.

The rats that ran in isolation, however, experienced no such gain. “Only animals that ran alone were vulnerable to its negative influence. They also had higher levels of the hormone compared to group runners.”

So running alone could be bad for the brain. Unless…

Unless you go for a really long run. “When isolated rats ran for a long time, they did see the same benefits as their short-term runner peers [who ran in groups] - but only when they had been running for a much longer period.”

The Princeton research team was led by Dr. Elizabeth Gould. In their article, “Social isolation delays the positive effects of running on adult neurogenesis” (aka “The Stress of Running Alone” article), in the journal Nature Neuroscience, she explained, “In the absence of social interaction, a normally beneficial experience can exert a potentially deleterious influence on the brain.”

So what to do? Grab a friend and hit the trails. Or, if going solo, go long. Real long.

Fascinating research. It’s enough to make you…

Play, think…
J.R. Atwood

In my very first post on this blog, I referenced a book called Spark, the most successful and accessible mass-market publication that explains the science of, and relationship between, physical exercise and overall mental health.

John Ratey, the book’s author and an associate professor of psychiatry at Harvard Medical School, says “[I] cannot underestimate how important regular exercise is in improving the function and performance of the brain. … Exercise stimulates our gray matter to produce Miracle-Gro for the brain. It’s such a wonderful medicine.”

The more rigorous the physical exercise, the better it is for your brain. But as noted in “Train Your Brain: Can Jogging Make You Smarter?“, an article by Simon Usborne in The Independent (UK), “Even regular brisk walks can books memory, alleviate stress, enhance intelligence, and allay aggression.”

The short article provides a fantastic CliffsNotes summary of Spark. Some excerpts:

Happiness

Evidence suggests that pounding the pavement can change the way our brains work to make us happier, or even stave off depression. “Exercise is as good as any anti-depressant I know,” Ratey claims.

Last December, scientists from Yale University wrote in the journal Nature Medicine that regular exertion affects the hippocampus, the area of the brain responsible for mood. Tests on mice showed that exercise activated a gene there called VGF, which is linked to a “growth factor” chemical involved in the development of new nerve cells. Tests show that this brain activation lifts a person’s mood.

Participants in one recent German survey were asked to walk quickly on a treadmill for 30 minutes a day over a 10-day period. At the end of the experiment, researchers recorded a significant drop in depression scores

Stress

We respond to stress in the same way our ancestors did – by adopting a “fight or flight” response. Adrenalin and other hormones are released into our bloodstreams and our muscles are primed for response. The problem is that, these days, stress is more likely to be brought on by a tricky PowerPoint presentation or a job interview than an attack by marauding lions, so the toxins that build up for a physical response have no outlet.

The results can be good; the cardiovascular system is accelerated and we can work harder (for a while, at least), but others are not so good; stress slows down the gastrointestinal system and reduces appetite, and can overexcite the brain, fuzzing our thought.

By responding to or anticipating stress with fight (kickboxing or judo, say) or flight (30 minutes on the treadmill, say, or 50 lengths of the pool), blood flow to the brain is increased, allowing the body to purge the potentially toxic by-products of stress.

According to Ratey, exercise also helps in the long term. “It builds up armies of antioxidants such as Vitamins E and C,” he says. “These help brain cells protect us from future stress.

Intelligence

Says Ratey, “Exercise doesn’t make you smarter, but what it does do is optimise the brain for learning.”

Physical activity boosts the flow of blood to the part of the brain that is responsible for memory and learning, promoting the production of new brain cells. Several schools in the US and the Netherlands have taken note. Pupils at Naperville Central High School near Chicago, for example, start the day with a fitness class they call “Zero Hour PE”. Equipped with heart monitors, they run laps of the playground, and teachers say exam results have soared since the keep-fit initiative kicked off.

Meanwhile, in Amsterdam, a test involving 241 people, aged 15-71, compared physical activity with the results of cognitive tasks. The researchers documented improved results among people who were more active, especially those in younger age groups.

Yet more research suggests that exercise boosts intelligence in the very, very young. Experiments on rats at the Delbrück Centre for Molecular Medicine in Berlin showed that baby rats born to mothers who were more active during pregnancy had 40 per cent more cells in the hippocampus, the area of the brain responsible for intelligence.

Aggression

“People assume exercise reduces aggression by burning energy. In fact, exercise changes your brain so you don’t feel aggressive in the first place,” says Ratey.

The frontal cortex is the part of the brain that decides whether you throw a punch or take something on the chin. Reduced activity in the region can result in an inability to control violent urges. “This area makes us evaluate the consequences of our actions,” Ratey says. Exercise increases activity in that area, boosting rational thought, which makes us less likely to lash out.

Memory

“When we’re exercising, we’re using nerve cells in the brain which help build up what I call brain fertilizer,” Ratey says. He is talking about new research that suggests exercise increases blood flow to the part of the brain responsible for memory, and improves its function.

In MRI scans on mice, conducted last year by neurologists at Columbia University Medical Centre in New York, the animals were shown to grow new brain cells in the dentate gyrus, which is affected in age-related memory decline.

“Exercise does more than anything we know of to boost memory.”

Addiction

Research by British scientists suggests that as little as five minutes of brisk walking can reduce the intensity of nicotine withdrawal symptoms. In the tests, researchers asked participants to rate their need for a cigarette after various types of physical exertion. Those who had exercised reported a reduced desire to smoke. “If we found the same effects in a drug, it would immediately be sold as an aid to help people quit smoking,” Adrian Taylor, the study’s lead author at the University of Exeter, said last year.

The principle is that exercise can stimulate production of the mood-enhancing hormone dopamine, which can, in turn, reduce smokers’ dependence on nicotine. “Dopamine works by replacing or satisfying the need for nicotine,” Ratey explains

So how much does one have to exercise to realize these results?

In Spark, Ratey advocates that we invest as much time and effort as we reasonably can afford into exercising. But as noted in the article, “You don’t have to become a marathon runner to benefit your brain. The mainstay of exercise is simple, brisk walking.”

Especially beneficial is interval training - “really pushing yourself for between 20 and 30 seconds so that you are momentarily exhausted.” Thirty seconds of sprinting, for example, sandwiched between two minutes of walking, for a total of 20-30 minutes, four-to-five times a day, will radically boost your brain power.

“The side effects on the body aren’t bad either - I lost 10 pounds in no time,” Professor Ratey says.

Play, think…
J.R. Atwood