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

We evaluated the influence of 12weeks of high-intensity interval training [HIIT; repeated 4min cycling at 90% of maximal oxygen uptake (V.O2max) interspersed with 3min rest, 200-300kJ per session, 3 or 4days each week] and work-equivalent moderate-intensity continuous training (MICT; continuous cycling at 60% V.O2max) on resting cardiac troponinT (cTnT) and the appearance of exercise-induced cTnT. Forty-eight sedentary obese young women were randomly assigned to HIIT, MICT or a control group. The V.O2max and body composition were measured before and after training. At baseline, cTnT was assessed using a high-sensitivity assay at rest and immediately, 2 and 4h after 45min cycling at 60% V.O2max. After a 12week training period, cTnT was assessed before and after 45min cycling at the same relative and absolute intensities as before training. Training led to higher V.O2max and lower fat mass in both HIIT and MICT groups (all P<0.05). Before training, cTnT was significantly elevated in all three groups (by 35-118%, all P<0.05) with acute exercise. After training, both resting and postexercise cTnT concentrations (same relative intensity) were similar to pretraining values. In contrast, postexercise cTnT (same absolute intensity, which represented a smaller exercise stimulus) was not elevated from rest in both HIIT and MICT groups. In conclusion, 12weeks of either HIIT or MICT largely abolished the postexercise elevation of cTnT concentration when exercise was performed at the same absolute intensity. There was, however, no impact of training on resting cTnT or postexercise appearance of cTnT for exercise performed at the same relative intensity.