Cardiac troponins after a downhill marathon

Cardiac Troponin-T Release After Sport and Differences by Age, Sex, Training Type, Volume, and Intensity: A Critical Review

BACKGROUND

Postexercise release of cardiac troponin (cTn) is a well-known phenomenon, although the influence of various confounders remains unclear. The aim of this critical review was to analyze the postexercise release of cTn according to age, sex, different types of sport, exercise intensity and duration, and training level.

DATA SOURCES

A literature search was performed within the National Library of Medicine using the following keywords: cTn, peak, release, and exercise. The search was further refined by adding the keywords athletes, children/adolescents, and sport.

MAIN RESULTS

For final analysis, 52 studies were included: 43 adult studies, 4 pediatric studies, and 5 with a mixed population of adults and children. Several studies have investigated the kinetics of cTn response after exercise with different biomarkers. The current evidence suggests that sport intensity and duration have significant effects on postexercise cTn elevation, whereas the influence of the type of sport, age, and sex have been not completely defined yet. Most data were obtained during endurance races, whereas evidence is limited (or almost absent), particularly for mixed sports. Data on young adults and professional athletes are limited. Finally, studies on women are extremely limited, and those for non-White are absent.

CONCLUSIONS

Postexercise release of cTn can be observed both in young and master athletes and usually represents a physiological phenomenon; however, more rarely, it may unmask a subclinical cardiac disease. The influence of different confounders (age, sex, sport type/intensity/duration, and training level) should be better clarified to establish individualized ranges of normality for postexercise cTn elevation.

Troponin and exercise

Cardiac troponins are the preferred biomarkers in diagnostic of myocardial infarction, but these markers also can rise in response to exercise. Multiple studies have assessed troponins post-exercise, but the results have varied and there have been disagreements about the mechanism of troponin release. The aim of this paper was to review the literature, and to consider factors and mechanisms regarding exercise-induced increase of troponin. 145 studies were found after a search in pubmed and inclusion of additional articles found in the reference list of the first articles. Results showed that troponin rises in 0-100% of subjects after prolonged heavy exercise like marathon, but also after short-term and intermittent exercise like 30min of running and basketball. The variation can be due to factors like intensity, age, training experience, variation in sample size, blood sample timing and troponin assay. The pattern of troponin level post-exercise corresponds to release from the cytosolic compartment of cardiomyocytes. Increased membrane permeability might be caused by production of reactive oxygen species or alterations in calcium, pH, glucose/fat metabolism or in communication between integrins. Other suggested mechanisms are increased cardiovascular stress, inflammation, vasculitis, release of troponin degradation products in "blebs", dehydration, impaired renal clearance and expression of cardiac troponin in skeletal muscle. It can be concluded that both heavy and light exercise may cause elevated troponin, which have to be considered when patient are suspected to have a myocardial infarction. Several factors probably influence post-exercise levels of troponin, but the mechanism of release is most likely physiologic.

Post-exercise left ventricular dysfunction measured after a long-duration cycling event

Background

In this research, an extension to our previous work published in the Clinical Journal of Sports Medicine in 2009, we studied subjects that differed in terms of age and training status and assessed the impact of prolonged exercise on systolic and left ventricular diastolic function and cardiac biomarkers levels, recognized as identifiers of cardiac damage and dysfunction. We also assessed the possible influence of event duration, exercise intensity and weight loss (dehydration) on left ventricular diastolic function.

Findings

Ninety-one male cyclists were assessed by echocardiography and serum biomarkers before and after the 2005 Quebrantahuesos cycling event (206 km long and with an accumulated slope of 3800 m). Cardiac function was assessed by echocardiography and cardiac biomarkers were assessed in blood serum. Echocardiograms measured left ventricular internal dimension during diastole and systole, left ventricular posterior wall thickness during diastole, interventricular septum thickness during diastole, left ventricular ejection fraction and diastolic filling. The heart rate of 50 cyclists was also monitored during the race to evaluate exercise intensity. Echocardiograph results indicated that left ventricular diastolic and systolic function decreased after the race, with systolic function reduced to a significant degree. Left ventricular ejection fraction was below 55% in 29 cyclists. The decrease in left ventricular systolic and diastolic function did not correlate with age, training status, race duration, weight loss or exercise intensity.

Conclusions

Left ventricular systolic and diastolic function was reduced and cardiac biomarkers were increased after the cycling event, but the mechanisms behind such outcomes remain unclear.

Cardiac troponins in young marathon runners

Cardiac troponin increases are common in adult marathon finishers. However, data on troponin values for young marathon runners are scarce. Forty young runners (20 healthy male and 20 female) 13 to 17 years old participated in this study. Blood samples were taken before, immediately after, and 24 hours after the race for determination of cardiac troponin T (cTnT) and troponin I (cTnI). Thirty-seven runners completed the race with a mean finishing time of 4 hours 53 minutes. No participant developed an adverse medical event during or after the race. In 30 of 37 participants, levels of cTnT and/or cTnI exceeded upper reference limits of 0.01 and 0.1 ng/ml immediately after the race, and in 3 participants these levels were even higher than the reference range for acute myocardial infarction (>0.1 and >0.5 ng/ml for cTnT and cTnI, respectively). Twenty-four hours after the race no participant had troponin levels exceeding the upper reference limits. Average increases of troponin levels did not differ between sexes. In conclusion, this is the first study to show that cardiac troponin levels increase to a similar extent in male and female adolescent marathon runners as observed in adults. Rapid recovery of troponin levels after a race is indicative of a physiologic rather than a pathologic response.

Cardiac biomarkers and exercise duration and intensity during a cycle-touring event

OBJECTIVE

To determine the influence of age, training status, race time, and exercise intensity on the appearance of cardiac biomarkers after a cycle-touring event.

DESIGN

Pre-post exercise measurements.

SETTING

University of Zaragoza, Zaragoza, Spain.

PARTICIPANTS

Ninety-one amateur cyclists.

INTERVENTION

The 2005 Quebrantahuesos cycle-touring event (distance: 206 km; altitude difference: 3800 m).

MAIN OUTCOME MEASURES

Cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) were measured the day before and immediately after the race. Heart rate (HR) monitoring was performed on 55 cyclists during the race to evaluate exercise intensity.

RESULTS

cTnI and NT-pro-BNP were significantly elevated immediately post race, with 43% of participants exhibiting cTnI levels greater than 0.04 microg/L and 65% of the participants measuring NT-pro-BNP levels greater than 125 ng/L. The cTnI increase was significantly associated with mean exercise intensity HR (r = 0.36, P < 0.01) but was not associated with age, training status, or race time. The increase in NT-pro-BNP correlated with race time (r = 0.40, P < 0.001) and training status (r = -0.36, P < 0.001) but was not associated with age or exercise intensity HR measures.

CONCLUSIONS

These results suggest that, in part, exercise intensity (HR) is responsible for the cTnI increase and that race time is responsible for the increase in NT-pro-BNP. Future standardized endurance exercise trials are recommended to further elucidate the potentially differential effects of training status, exercise time, and intensity on post-exercise increases in cTnI and NT-pro-BNP.