Adverse Cardiometabolic responses to exercise: A review and opinion

On May 30th 2012 the New York times published an article (http://well.blogs.nytimes.com/2012/05/30/can-exercise-be-bad-for-you/) on a study by Bouchard et al (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0037887) which had discovered significant cardiometabolic adverse reactions in patients following exercise interventions. This report combined the findings of 6 studies and had a total of 1,687 subjects of various levels of health, risk factors, gender and age. These findings were quite profound in that currently exercise particularly aerobic exercise is recommended for patients to prevent or reduce the risk of cardiovascular pathologies. There have been numerous studies that support these claims; all one would have to do is search “exercise and cardiac benefits” to PubMed or even google and a plethora of articles in respectable journals would appear. It must be noted that the overwhelming majority of the interventions evaluated were endurance exercise, only two of the studies evaluated had subjects perform resistance exercise and of those two only one of the studies’ data was used in this report.

The authors of this study are all well known and reputable and after reading the article myself I feel that their findings are solid. They effectively controlled for error in measurement by only classifying AR to be greater than 2  standard deviations from the average to even be considered ‘significant”. Their statistical analyses also controlled for bias due to duration, gender and other variables. Their population pool was enormous and quite variable and the dosage of exercise was considerably mixed which made these findings very generalizable.

With all this being said I would agree with the authors in that stating though these findings do suggest that their may be a “statistically significant” percentage of people who experienced a deleterious effect from exercise, about 10% on average, one must must also realize that close to 90% of people did have positive benefit. When you take a step back and re-review these findings you realize that these findings are not that surprising. Any intervention there is always a chance for negative effects. Look at all of the drug therapies that are currently implemented, almost all could cause an adverse effect in a given patient. We are all very similar but we are all different at the cellular level and molecular level. If we were to abandon every intervention because 10% of the population have a negative side-effect we wouldn’t have that many left. The beauty of the healthcare system is that we have such variability in the way we can intervene with patients and treat pathologies. When the standard doesn’t work you try something else. The same should be said for exercise as well.

As a future physical therapist I feel that this issue is something that we can get involved in. By that I mean what the authors suggested in their discussion which is that there is a 20-30% genetic link for some of these ARs. This finding suggests the need for blood work and pre-screening of patient before and exercise plan is ever administered especially to “at risk” patients. The most effective and efficient way to pre-screen someone for exercise is to administer a stress test which physical therapists are now doing more often with the progression of cardiac rehab. We have a chance to really get involve in this and I hope more research is done in the future in evaluating the ability of a stress test’s and concurrent blood work data at predicting ARs for patients. Too often exercise is prescribed capriciously with out considering that you may hurt your patient if you aren’t careful and treat the intervention as a medicine.

I would also like future research to look at the combination of resistance exercise and aerobic on metabolic risk factors. This study only had one group that did both and they had ARs but less in total, they also had one of the smaller sample sizes and were not American.

That’s enough from me take a look at the article and leave your comments below. Time to play cricket followed by watching the UFC fights.

Cheers guys

-Rich

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