In older long-distance walkers, troponin I levels above the 99th percentile were associated with higher risk for mortality and CV events.
According to a study published in Circulation, in a cohort of 725 participants (aged 54 to 69 years; 38% women; 9% with diabetes), 27% of those who walked for a distance of 30 to 50 km had troponin I concentrations greater than 0.04 µg/L experienced a major adverse CV event, including MI, stroke, HF, revascularization or sudden cardiac arrest, or died compared with older adults with troponin levels of 0.04 µg/L or less (HR = 2.48; 95% CI, 1.29–4.78).
“Exercise-induced elevations in cardiac troponin concentrations have been considered to be benign for many years,” Thijs Eijsvogels, PhD, exercise physiologist in the department of physiology at the Radboud University Medical Center, Nijmegen, Netherlands, and colleagues wrote. “The present study challenges this concept, as we found a lower event-free survival in participants with post-exercise cardiac troponin concentrations above the 99th percentile (clinical cut-off). These clinically relevant observations suggest that elevated troponin concentrations following exercise may be an early marker of subclinical cardiac pathology.”
This study was performed during the Nijmegen Four Days Marches, the largest walking event in the world, during which participants walk 30, 40, 50 or 55 km per day for 4 consecutive days.
Study participants completed a questionnaire, answering questions about CV health and prescribed medications, and then were categorized as having CVD, CV risk factors (ie, treated hypertension, hypercholesterolemia or diabetes) or no CVD or CV risk factors at baseline.
Researchers then took a 10-mL venous blood sample 2 days prior to the event and again approximately 10 minutes after completion of walking on the first day.
Of the enrolled participants (n = 725), 14% had CVD, 26% had only CV risk factors and 60% had no CVD or CV risk factors at baseline and were used as a control group. Mean follow-up was 46 months.
The participants in this study walked approximately 8 hours at 68% of their maximum heart rate, according to the study. At baseline, nine participants (1%) had a baseline troponin concentration greater than 0.04 µg/L. After walking, troponin I concentrations increased significantly (P < .001); 63 participants (9%) had a concentration greater than 0.04 µg/L.
During follow-up, 29 participants died and 33 had major adverse CV events.
“Future studies are needed to confirm outcomes of the present study, preferably with a larger sample size and longer follow-up,” Eijsvogels told Cardiology Today. “Furthermore, findings from our study cannot be directly extrapolated to other types of exercise, such as running and cycling, in which greater exercise-induced cardiac troponin elevations have been observed. Finally, mechanistic studies are needed to unravel how exercise can increase blood concentrations of cardiac troponins.” – by Scott Buzby
For more information:
Thijs Eijsvogels , PhD , can be reached at email@example.com; Twitter: @ThijsEijsvogels.
Disclosures: Eijsvogels reports no relevant financial disclosures. The other authors report no relevant financial disclosures.