The Effects of Circadian Rhythms and Exercise Preconditioning on Cardiac Troponin T Levels Following Graded Exercise

Nie, J, Zhang, R, Zhang, H, Shi, Q, George, K and Kong, Z (2025) The Effects of Circadian Rhythms and Exercise Preconditioning on Cardiac Troponin T Levels Following Graded Exercise. European Journal of Sport Science, 25 (5). ISSN 1746-1391

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Abstract

This study explored the impact of circadian rhythms on the circulating cardiac troponin T (cTnT) response to a graded exercise test (GXT) and examined whether an initial GXT influenced the cTnT response to a subsequent GXT performed 7–9 days later. Twenty-one healthy young males (age: 20.6 ± 2.2 years, body mass index: 22.2 ± 2.6 kg/m2, V̇O2max: 31.8 ± 8.7 mL.kg−1.min−1) participated in three trials: an initial GXT (GXT1), a resting control trial (CON) and a second GXT (GXT2), separated by at least 72 h. The serum cTnT levels were measured pre-exercise, 4 h post-exercise or during the control. In GXT1, the cTnT levels did not show significant changes (median [range], pre: 3.80 [3.00–10.59] ng.L−1, post: 4.22 [3.00–9.08] ng.L−1, p > 0.05). During CON, the cTnT levels decreased significantly from morning to early afternoon (3.52 [3.00–10.84] vs. 3.00 [3.00–7.57] ng.L−1, p < 0.05), reflecting a circadian rhythm. Interestingly, GXT1 appeared to prevent this circadian decline. Furthermore, in GXT2, the cTnT levels significantly decreased post-exercise (4.13 [3.00–15.48] vs. 3.24 [3.00–12.96] ng.L−1, p < 0.05), suggesting a possible “late exercise preconditioning” effect from GXT1. These findings suggest that GXT can interact with circadian rhythms, altering cTnT dynamics, and that prior exercise may induce prolonged cardioprotective effects. This study highlights the importance of accounting for circadian variability and late preconditioning effects in future research on exercise-induced cTnT release.

Item Type:	Article
Uncontrolled Keywords:	42 Health Sciences; 4207 Sports Science and Exercise; Sleep Research; Cardiovascular; Physical Activity; Prevention; 6.7 Physical; 0913 Mechanical Engineering; 1106 Human Movement and Sports Sciences; Sport Sciences; 4207 Sports science and exercise; 5201 Applied and developmental psychology
Subjects:	R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions:	Sport and Exercise Sciences
Publisher:	Wiley
Date of acceptance:	28 March 2025
Date of first compliant Open Access:	10 April 2025
Date Deposited:	10 Apr 2025 11:37
Last Modified:	10 Apr 2025 11:45
DOI or ID number:	10.1002/ejsc.12294
URI:	https://researchonline.ljmu.ac.uk/id/eprint/26149

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