Friday, March 16, 2007

Prolonged Strenuous Activity May Cause Increase in Troponin Levels

Troponin levels may increase significantly in marathon runners, even reaching levels diagnostic for acute myocardial infarction, according to results of a study involving participants in the 2002 Boston Marathon.
Dr. Elizabeth B. Fortescue and her colleagues, based at Children's Hospital Boston, recruited 482 runners a day or two before the marathon. As the authors note in the Annals of Emergency Medicine for February, the cohort was heterogeneous in terms of experience, age, and fitness.
The subjects completed questionnaires prior to the race, including demographics and medical history. Immediately after completing the 26.2-mile course, subjects provided a blood sample and answered questions about symptoms during the race.
Overall, 68% of runners had some degree of post-race troponin level increase, ranging from 0.02 to 0.74 ng/mL for troponin T and 0.05 to 4.17 ng/mL for troponin I.
Dr. Fortescue's team defined significantly elevated troponin T as at least 0.075 ng/mL, and elevated troponin I as at least 0.50 ng/mL, based on reference values diagnostic for myocardial infarction. Fifty-five of the runners (11%) had troponin levels in this range.
Eight subjects had never before participated in a marathon, and their risk of elevated serum troponin was 3-fold higher than for experienced runners. Age less than 30 years and female gender were also associated with elevated troponin levels.
http://www.medscape.com/viewarticle/553373?src=mp

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