Friday, September 23, 2011

How much exercise should I get?

For years, I got very little exercise. I broke my kneecap when I was thirteen, had it immobilized for months, never got rehabbed afterwards, and was pretty much resigned to no sports for years afterward.

When I finally decided to start biking again (a low impact form of exercise I figured would be easier on my knees), I found that I had to work through significant tendonitis pain brought on by suddenly using a joint that had been inactive for years and which was damaged to begin with. Ultimately, perseverance saw me through this, and I’m back on track and training for a half marathon – not bad for someone who dropped out of his high school cross country team.

Anyway, I only provide this story to illustrate a point. Not every seemingly sporty young person you see out jogging on the weekend is a born athlete. Everyone has to start somewhere, and some of us have a slightly higher hill to climb before we can get there. So take those as words of inspiration as we discuss exercise.

At this point, everyone knows that exercise is good for you. It helps prevent a number of chronic diseases, including high cholesterol, some cancers, high blood pressure, osteoporosis, diabetes, and depression, to name a few. A few weeks ago, I blogged about a study showing that regular exercise is one behavior that can help you live longer, too. But how much should you get and what counts as exercise?

The current consensus is that every adult should get 150 minutes a week of moderate aerobic activity and strength training twice a week, or 75 minutes a week of vigorous aerobic activity and strength training. These guidelines have been by numerous high-profile organizations, including the CDC, the US Department of Health and Human Services, and the American Heart Association.

OK, so what is ‘moderate aerobic activity’? According to the folks writing the guidelines, this category includes brisk walking, water aerobics, light biking, ballroom dancing, or general gardening. 150 minutes a week breaks down into 30 minutes five days a week, and many of the websites also suggest that this can be done in 10-minute chunks. Doesn’t sound so bad, right? An afternoon of gardening and a walk around a local pond has you well on your way. Biking to work also counts. If you walk your dog daily, you may be pretty much covered. And heck, if you go out ballroom dancing, well then you win style points in addition to getting exercise.

What about ‘strength training’? Here things are a bit vaguer, as no time or weight guidelines are given, but examples include push-ups, sit-ups, and weight training, which some people find imposing, as well as everyday-life activities, such as lifting heavy loads and doing heavy gardening.

‘Vigorous aerobic activity’ covers most of what we think of as ‘exercise’, including jogging, running, swimming laps, playing tennis or other sports, vigorous biking, or hiking. When discussing this level of activity, most NDs say, ‘Some activity which causes you to break a sweat.’ For those who want more information, the CDC’s website provides excellent resources about the benefits of higher amounts of exercise as well as how to measure the intensity of your physical activity.

The general theme with these activities is to make using your body part of your routine. It doesn’t need to be elaborate, regimented, grueling or strenuous, but it’s important that you do it regularly. You don’t have to be a trained athlete to prevent chronic disease, but you can’t be sedentary. Our bodies are built to move, so get out there and do what generations on generations of your ancestors did – move around and have some fun!