Impact of high-intensity interval training and moderate-intensity continuous training on resting and post-exercise cardiac troponin T concentration

Abstract

We evaluated the influence of 12 weeks high-intensity interval training (HIIT, repeated 4-min cycling at 90% V̇O_2max interspersed with 3-min rest, 200–300 KJ/session, 3–4 days wk⁻¹) and work-equivalent moderate-intensity continuous training (MICT, continuous cycling at 60% V̇O_2max) on resting cardiac troponin T (cTnT) as well as exercise-induced cTnT appearance. Forty-eight sedentary obese young women were randomly assigned to HIIT, MICT, or a control group. V̇O_2max and body composition were measured before and after training. At baseline, cTnT was assessed using a high-sensitivity assay at rest and immediately, 2 h and 4 h after 45-min cycling at 60% V̇O_2max. After a 12-wk training period, cTnT was assessed before and after 45-min cycling at the same relative and absolute intensities as before training. Training led to higher V̇O_2max and lower fat mass in both HIIT and MICT (all P < 0.05). Before training, cTnT was significantly elevated in all three groups (35 to 118%, all P < 0.05) with acute exercise. After training both resting and post-exercise cTnT levels (same relative intensity) were similar to pre-training values. In contrast, post-exercise cTnT (same absolute intensity, which represented a smaller exercise stimulus) was not elevated from rest in both HIIT and MICT groups. In conclusion, 12 weeks of either HIIT or MICT largely abolished the elevation of post-exercise cTnT concentration when exercise was performed at the same absolute intensity. There was, however, no impact of training on resting cTnT or post-exercise cTnT appearance for exercise performed at the same relative intensity.

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