Abstract:Key pointsr Strenuous endurance exercise induces transient functional and biochemical cardiac perturbations that persist for 24-48 h.r The magnitude and time-course of exercise-induced reductions in ventricular function and increases in cardiac injury markers are influenced by the intensity and duration of exercise.r In a human experimental model, exercise-induced reductions in ventricular strain and increases in cardiac troponin are greater, and persist for longer, when exercise is performed within the heavy-… Show more
“…Although no horse, at any time, in the our study exceeded the URL for cTnT concentrations (i.e. 23.2 ng/L with the hscTnT assay), similar to results from exercise studies in humans, it may be normal for healthy horses to actually meet or possibly exceed the URL for cTnT concentrations at these peak time‐points . Also, the cTnT concentrations decreased at, and after, 12‐hour postrace in all horses that had concentrations above the LoD of the hscTnT assay.…”
BackgroundA “high‐sensitivity” cardiac troponin‐T (hscTnT) assay recently has been validated for use in horses and is a specific biomarker of myocardial damage. Postexercise release kinetics of cTnT utilizing the hscTnT assay have yet to be established in horses.ObjectivesTo determine: (1) cTnT release kinetics in racing Thoroughbreds after a high‐intensity 5/8th mile Chuckwagon race; (2) the effects of age on pre‐ and postrace cTnT concentrations; and (3) sampling guidelines for clinicians evaluating horses presenting after exercise.AnimalsSamples were obtained from 38 Thoroughbred geldings aged 5–16 years before racing and immediately, 2, 3, 4, 6, 12, and 24 hour postrace.MethodsProspective, observational study with convenience sampling. A fifth‐generation hscTnT assay was used for plasma sample analysis, and concentrations were compared at all time‐points. Correlations were determined between cTnT concentrations and age. Biochemistry analysis was performed to assess rhabdomyolysis, renal failure, and exercise‐induced dehydration.ResultsAll horses with measureable cTnT concentrations had significant postexercise increases in cTnT with a median peak (8.0 ng/L) at 3‐hour postrace. All horses had peak postexercise cTnT concentrations 2‐ to 6‐hour postrace ≤ the 99th percentile upper reference limit of 23.2 ng/L, after which all cTnT concentrations decreased until returning to baseline by 12–24 hours. There was no correlation over time between cTnT concentrations and age.Conclusions and Clinical ImportanceIn racing Thoroughbreds completing short‐duration, high‐intensity Chuckwagon races, cTnT concentrations are expected to be increased 2‐ to 6‐hour postrace and to decrease by 12–24 hours while remaining ≤23.2 ng/L throughout. This study contributes to establishing guidelines for clinical use of the hscTnT assay in exercising horses.
“…Although no horse, at any time, in the our study exceeded the URL for cTnT concentrations (i.e. 23.2 ng/L with the hscTnT assay), similar to results from exercise studies in humans, it may be normal for healthy horses to actually meet or possibly exceed the URL for cTnT concentrations at these peak time‐points . Also, the cTnT concentrations decreased at, and after, 12‐hour postrace in all horses that had concentrations above the LoD of the hscTnT assay.…”
BackgroundA “high‐sensitivity” cardiac troponin‐T (hscTnT) assay recently has been validated for use in horses and is a specific biomarker of myocardial damage. Postexercise release kinetics of cTnT utilizing the hscTnT assay have yet to be established in horses.ObjectivesTo determine: (1) cTnT release kinetics in racing Thoroughbreds after a high‐intensity 5/8th mile Chuckwagon race; (2) the effects of age on pre‐ and postrace cTnT concentrations; and (3) sampling guidelines for clinicians evaluating horses presenting after exercise.AnimalsSamples were obtained from 38 Thoroughbred geldings aged 5–16 years before racing and immediately, 2, 3, 4, 6, 12, and 24 hour postrace.MethodsProspective, observational study with convenience sampling. A fifth‐generation hscTnT assay was used for plasma sample analysis, and concentrations were compared at all time‐points. Correlations were determined between cTnT concentrations and age. Biochemistry analysis was performed to assess rhabdomyolysis, renal failure, and exercise‐induced dehydration.ResultsAll horses with measureable cTnT concentrations had significant postexercise increases in cTnT with a median peak (8.0 ng/L) at 3‐hour postrace. All horses had peak postexercise cTnT concentrations 2‐ to 6‐hour postrace ≤ the 99th percentile upper reference limit of 23.2 ng/L, after which all cTnT concentrations decreased until returning to baseline by 12–24 hours. There was no correlation over time between cTnT concentrations and age.Conclusions and Clinical ImportanceIn racing Thoroughbreds completing short‐duration, high‐intensity Chuckwagon races, cTnT concentrations are expected to be increased 2‐ to 6‐hour postrace and to decrease by 12–24 hours while remaining ≤23.2 ng/L throughout. This study contributes to establishing guidelines for clinical use of the hscTnT assay in exercising horses.
“…Sports medicine providers and organizations could use limited echocardiography to optimize athletes' performance and health. A growing body of evidence suggests that the relationship between the exercise dose and cardiovascular health is a U‐shaped curve: extremely low and extremely high exercise doses appear to negatively affect cardiovascular health . Implementation of limited echocardiography would allow sports medicine providers to monitor individual athletes' responses to exercise.…”
Athletes' hearts have been studied for adaptive changes in response to exercise. Physiologic changes are normal responses to intense athletic training regimens, whereas pathologic changes predispose athletes to sudden cardiac death. The two alterations overlap in clinical presentation. Research continues to investigate the upper limits of cardiac remodeling to aid clinical decision making. Studying normal changes that occur in response to exercise will advance physicians' understanding of physiologic responses to exercise and potentially improve clinical distinction. To expand this body of knowledge, we present an observational case series that describes morphologic changes in athlete's hearts concurrent with performance measurements.
“…In a recent article in The Journal of Physiology , Stewart et al . () investigated the exercise threshold topic by studying the influence of exercise intensity and duration on functional and biochemical markers of cardiac stress.…”
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