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

Abstract

We evaluated the influence of 12 weeks of high-intensity interval training [HIIT; repeated 4 min cycling at 90% of maximal oxygen uptake (V̇O2max) interspersed with 3 min rest, 200-300 kJ per session, 3 or 4 days each week] and work-equivalent moderate-intensity continuous training (MICT; continuous cycling at 60% V̇O2max) on resting cardiac troponin T (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 V̇O2max 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 4 h after 45 min cycling at 60% V̇O2max. After a 12 week 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 V̇O2max 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, 12 weeks 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.

The impact of high‐intensity interval training on the cTnT response to acute exercise in sedentary obese young women

“…While previously thought to be a phenomenon exclusive to ultra‐endurance exercise, cTn elevation has also recently been found to be present after high‐intensity exercise of relatively short duration such as half‐marathon race . Our recent study suggests that the exercise‐induced elevation of cTnT might occur even after a typical bout of physical activity recommended by public health guidelines . In the present study, we complement our recent findings by showing the “all‐out” sprints in RSE with very short duration also resulted in substantial cTnT elevation in most participants, but the increase was somewhat less than that in HIE or SIE, likely due to a much lower total mechanical work of RSE (RSE vs HIE or SIE: ~50 vs 200 kJ).…”

“…We recently assessed the effects of a 12‐week training (~44 total sessions) program of interval exercise on cTnT response to continuous exercise . Thus, the present study complements our prior work.…”

“…O 2max was determined using a graded cycling exercise protocol that has been described previously . The participants began at 50 W with a pedal frequency of 60 rpm on a cycle ergometer (Monark, 839E, Sweden); power output was increased by 20 W every 2 minutes until volitional exhaustion.…”

“…There is a burgeoning evidence base that cardiac troponin (cTn, cTnT, and/or cTnI), a biomarker pathognomic for cardiomyocyte damage, is elevated after continuous prolonged exercise . There are very few data describing the cTn response to high‐intensity interval exercise (HIE) . HIE typically involves repeated bouts of relatively intense exercise interspersed by short periods of recovery and is growing in popularity in cardiac rehabilitation, health, and fitness applications .…”

“…Data related to the impact of long‐term training upon the cTn response to an acute exercise stimulus is currently limited, contradictory, and has mainly employed moderate‐intensity continuous training (MICT) interventions . Recently, we demonstrated a 12‐week MICT or HIE training program largely abolished the post‐continuous exercise elevation of cTnT at the same absolute intensity but had no effects on the post‐continuous exercise appearance of cTnT at the same relative intensity . To date, however, no study had directly determined the effects of multiple episodes of interval exercise on the appearance of acute interval exercise‐induced cTn.…”