Thursday, October 3, 2013

Exercise: The Best Medicine

A very interesting article was just published in the British Medical Journal. The researchers reviewed meta-analysis studies that compared exercise and medications to each other or placebo and the effects they had on the risk of death. Collectively, these studies suggest that exercise and medications have similar outcomes when it comes to lowering death. 

A quick lesson about Meta-Analyses:  Any time you see an article that talks about results of a meta-analysis, you should proceed with caution!  A meta-analysis is tricky business. Researchers combine data from several studies and reanalyze it as one study. They do this when there are few large, definitive studies in a specific research area. So they take a bunch of studies that meet their specific criteria as far as study design, research variables, study participant characteristics, etc. and crunch the data together. This method is imperfect at best because no matter how similar studies may be, the differences in how the data were gathered can result in much less precise results when you put all the data together. That said, these studies can be useful in areas where larger studies are lacking.  And if the researchers conducting the meta-analyses use rigorous methods, then the data can at least be somewhat useful. 

What this study found: The results of this particular meta-analyses are particular interesting and encouraging. The researchers looked at studies that looked at deaths related to heart disease, stroke, heart failure, and pre-diabetes. The risk of all of these diseases can be lowered by diet and exercise. But no one has ever shown if exercise by itself can reduce the risk of dying from these diseases or if exercise is as effective as medicines in lowering the risk of dying from these diseases. 
For heart disease and prediabetes, the researchers found that exercise was just as effective as medicines for preventing deaths caused by these two common diseases. In the case of stroke, exercise was found to be more effective than medicines in preventing death from stroke. 

What kind of exercise? Because the studies reviewed were meta-analyses, the exercise programs in each of the studies were different. Most used a combination of muscle strengthening exercises and aerobic exercise like walking, biking, or swimming.
The exciting message – that we do have to approach with caution – exercise may be as effective – and in some cases more effective – than medicines when it comes to treating several  of the diseases that Americans are most likely to die from. Since medicines can be expensive and have possible side effects, this is a good news message. And don’t forget that exercise has other benefits as well such as improving mood and your ability to do the day to day activities you need and want to do.

Beth Kitchin, PhD, RDN
Assistant Professor,Nutrition Sciences
University of Alabama at Birmingham

Naci, H. & Ioannidis, J. Comparative effectiveness of exercise and drug interventions on mortality outcomes: metaepidemiological study. 2013. BMJ 347:f5577.

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