The impact of exercise modality and menstrual cycle phase on circulating cardiac troponin T

Abstract Objectives It is unclear whether exercise modality (moderate-intensity continuous [MCE]; high-intensity interval [HIE]) and menstrual cycle phase (follicular [FP]; luteal [LP]), individually or in combination, mediate the commonly observed exercise-induced elevation in cardiac troponin T (cTnT). This study examines cTnT responses to MCE and HIE during both the FP and LP. Design Randomised crossover study. Methods Seventeen healthy, eumenorrheic women completed four trials including MCE (60% VO2max steady-state cycling until 300 kJ) and work‐equivalent HIE (repeated 4-minute cycling at 90% VO2max interspersed with 3-minute rest) during both the FP and LP. The FP and LP were verified based on ovarian hormones. Serum cTnT was assessed using a high-sensitivity assay before, immediately after, and 1 (1HR), 3 (3HR) and 4 (4HR) hours after exercise. cTnT values were corrected for plasma volume changes. Results cTnT was significantly elevated (p 0.05) in peak post-exercise cTnT, which mostly occurred at 3HR, was seen among the four trials (median [range], ng.l-1: 5.2 [1.7-18.1] after MCE during FP; 4.8 [1.7-24.9] after MCE during LP, 8.2 [3.9-24.8] after HIE during FP and 6.9 [1.7-23.1] after HIE during LP). Conclusions A single 300 kJ bout of both MCE or HIE resulted in a significant post-exercise increase in cTnT, with no differences in peak cTnT response between menstrual cycle phases or between exercise modes, but the cTnT elevation occurs slightly earlier after HIE.