Tuesday, June 5, 2012

Adverse reaction

Some fascinating research coming out at the moment on the potential negative effects of exercise. Since this goes counter to what we are all told such studies warrant close examination but certainly should not be simply dismissed because they don't fit the dominant paradigm.

First up, from the Mayo Clinic Proceedings this month: Potential Adverse Cardiovascular Effects From Excessive Endurance Exercise
where they review some of the evidence that long-term excessive endurance exercise can induce pathologic structural remodeling of the heart and large arteries.

Physically active people are much healthier than their sedentary counterparts. Exercise is one of the most important things you need to do on a daily basis,” he explains. “But what this paper points out is that a lot of people do not understand that the lion’s share of health benefits accrue at a relatively modest level. Extreme exercise is not really conducive to great cardiovascular health. Beyond 30-60 minutes per day, you reach a point of diminishing returns.

Second, and of more general relevance to the general population, a paper in PLoS ONE this week : Adverse Metabolic Response to Regular Exercise: Is It a Rare or Common Occurrence?

The review of six previous studies on exercise found that working out worsened at least one measure of heart risk — blood pressure, insulin level or levels of HDL cholesterol or triglycerides — for about 10% of people. About 7% of people declined on at least two measures.
For a scientist this doesn't seem that surprising after some reflection - although, on average, exercise may lead to a favorable outcome there may be a range of responses from individuals that span a range from very favorable all the way down to an unfavorable change.

Unfortunately I think you can imagine the headlines:
For those looking for an excuse to avoid exercise, here's one 
Can Exercise Actually Be Bad For You?
Exercise could be, er, bad for your heart, study says

Oh, and tomorrow is National Running Day...

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