How Much Exercise Do I Need?
In my last posting called “Exercise, Stress and The Brain,” I wrote about the experiment that was done at the University of Colorado on the stress-reducing changes on the brain produced by exercise. In that experiment rats that ran for only three weeks did not show much reduction in stress-induced anxiety, but those that ran for at least six weeks did. “Something happened between three and six weeks,” says Benjamin Greenwood, Ph.D., a research associate in the Department of Integrative Physiology at the University of Colorado, who helped conduct the experiments. Then he goes onto say “It’s not clear how that translates” into an exercise prescription for humans. We may require more weeks of working out, or maybe less. And no one has yet studied how intense the exercise needs to be.
Imagine, here we are in 2010 with all the advancements in medical knowledge and we still can’t come up with some kind of universal exercise prescription? Interesting. Perhaps coming up with an exercise prescription is not a science, but maybe an art form. However, it’s hard for me to accept that medical science does not have a great deal to say about how much we should move our bodies. Perhaps it’s a mixture of both art and science. We can look at some recent studies to help us formulate an exercise prescription for most people.
Again, I pulled some information out from an article that Gretchen Reynolds wrote in the New York Times a few weeks ago http://well.blogs.nytimes.com/2009/12/30/phys-ed-how-much-exercise-to- avoid-feeling-gloomy/.
A reading of the latest sports science report makes it clear that the “amount of physical activity necessary to produce health benefits cannot yet be identified with a high degree of precision,” according to the authors of the 2008 Physical Activity Guidelines for Americans report http://www.health.gov/PAGuidelines/, which was produced by the Department of Health and Human Services and was based on the recommendations of an advisory committee of scientists. These experts waded through dozens of studies on the health effects of exercise, looking at the impacts that exercise can have on people’s risks for heart disease, obesity, diabetes, cancer, depression and, in general, premature death.
Despite the inconsistent results, caused in some part by even more inconsistent methodologies between the different studies, the advisory committee did ultimately reach some conclusions about how much – or, really, how little – exercise we should be doing. So here goes:
The committee concluded that a person needs to accumulate a weekly minimum of two and a half hours of a moderate activity, such as walking. Or a person could spend half as much time (an hour and 15 minutes) on a more robust form of exercise such as jogging, according to this committee, to have similar health effects.
Interestingly, they did not find that exercise beyond a certain point conferred significant additional health benefits. That is to say, that people who are the least active to start with get the most health benefit from starting to exercise. People who already are fit don’t necessarily get a big additional health benefit from adding more workout time to their regimens. Which is not to say that if you are a devoted runner or cyclist, you should reduce your workout time in 2010. It’s just you’re already well ahead in terms of health benefits. According to the Physical Activity Guidelines report, “ It has been estimated that people who are physically active for approximately seven hours a week have a 40 percent lower risk of dying early than those who are active for less than 30 minutes a week.”
Now we are getting somewhere.
So what does this mean as you plan your 2010 exercise routines? First, because “activity affects so many organs and pre-disease states,” according to Frank Booth, a professor in the department of biomedical sciences at the University of Missouri at Columbia, who has extensively studied the health effects of exercise, “any activity is better than no activity.” The bottom line here is do something. Booth adds “Inactivity is looking more and more like the one of the underlying causes of many chronic diseases,” And lastly, he adds, “you want to live to be 100, then don’t just sit all day.” Well there you go. I guess the scientists do have something to say about exercise.
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Exercise, Stress and The Brain
Gretchen Reynolds from the New York Times wrote, several Sunday’s ago, an interesting article about how scientists are looking at how exercise can make the brain more stress-resistant ( http://well.blogs.nytimes.com/2009/11/18/phys-ed-why-exercise-makes-yo u-less-anxious/ ). Researchers at Princeton University recently made a remarkable discovery that some of the neurons in rats that exercise respond differently to stress than the neurons of slothful rats.
Scientists have known for some time that exercise stimulates the creation of new brain cells (neurons) but not how, precisely, these neurons might be functionally different from other brain cells. Presented a few months ago at the annual meeting of the Society for Neuroscience in Chicago( http://www.sfn.org/am2009/ ) the researchers at Princeton University revealed their preliminary results of their remarkable discovery about the brains of rats that exercise.
In the experiment, scientists allowed one group of rats to run. Another set of rodents were not allowed to exercise. Then all of the rats swam in cold water, which they don’t like to do. Afterward, the scientists examined the animals’ brains. They found that the stress of the swimming activated neurons in all of the animals’ brains. But the youngest brain cells in the running rats, the cells that the scientists assumed were created by running, were less likely to express the genes. They generally remained quiet. The “cells born from running,” the researchers concluded, appeared to have been “specifically buffered from exposure to a stressful experience.” The rats had created, through running, a brain that seemed biochemically, molecularly, calm.
We all know that exercise is good for us, but we are now discovering how exercise helps us in different ways on a molecular level. Thanks now to improved research techniques and a growing understanding of the biochemistry and genetics, scientists are beginning to find out how exercise remodels the brain, making it more stress-resistant.
The stress-reducing changes wrought by exercise on the brain don’t happen overnight. However, as virtually every researcher agrees. In the University of Colorado experiments, for instance, rats that ran for only three weeks did not show much reduction in stress-induced anxiety, but those that ran for at least six weeks did. “Something happened between three and six weeks.” Says Benjamin Greenwood, Ph.D., a research associate in the Department of Integrative Physiology at the University of Colorado, who helped conduct the experiments( http://www.ncbi.nlm.nih.gov/pubmed/18300002 ). “It’s not clear how that translates” into an exercise prescription for humans. We may require more weeks of working out, or maybe less. And no one has yet studied how intense the exercise needs to be. But the lesson is “don’t quit,’ Greenwood says. Keep running, cycling or swimming. You may not feel a magical reduction of stress after your first jog, if you haven’t been exercising. But the molecular, biochemical changes will begin, Greenwood says, and eventually they become, he says, “profound.”
Here at oomphTV we strongly recommend any kind of exercise program to help give you both “oomph” and calmness in your life. Consider this study in the beginning of 2010 and take a look at the 94-year old runner Jack Kirk video for inspiration http://www.oomphtv.com/people-with-oomph-features-short-videos-of-peop le-over-forty-redefining-age/jack-kirk-the-dipsea-demon After reading this blogpost and viewing the video, create your own exercise program and don’t let it be just another New Year’s resolution. Happy New Year and best of luck! Please feel free to comment, we look forward to hearing from you in 2010.
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