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

Abstract

Aims This study characterized (a) the cardiac troponin T (cTnT) response to three forms of acute high‐intensity interval exercise (HIE), and (b) the impact of 12 weeks of HIE training on the cTnT response to acute exercise in sedentary obese young women. Methods Thirty‐six sedentary women were randomized to traditional HIE training (repeated 4‐minute cycling at 90% trueV˙O2max interspersed with 3‐minute rest, 200 kJ/session), work‐equivalent sprint interval exercise (SIE) training (repeated 1‐minute cycling at 120% trueV˙O2max interspersed with 1.5‐minute rest) or repeated‐sprint exercise (RSE) training (40 × 6‐second all‐out sprints interspersed with 9‐second rest) group. cTnT was assessed using a high‐sensitivity assay before and immediately, 3 and 4 hours after the 1st (PRE), 6th (EARLY), 20th (MID), and 44th (END) training session, respectively. Results cTnT was elevated (P < 0.05) after all forms of acute interval exercise at the PRE and EARLY assessment with cTnT response higher (P < 0.05) after HIE (307%) and SIE (318%) than RSE (142%) at the PRE assessment. All forms of acute interval exercise at MID and END had no effect on the cohort cTnT concentration post‐exercise (all P > 0.05). Conclusion For sedentary obese young women, both HIE and SIE, matched for total work, induced a similar elevation in cTnT after acute exercise with a smaller rise observed after RSE. By the 44th training session, almost no post‐exercise cTnT elevation was observed in all three groups. Such information is relevant for clinicians as it could improve medical decisionmaking.

The cardiac troponin response during high‐intensity interval training

“…In light of the current attractiveness of high-intensity interval training in athletes as well as patients suffering from cardiorespiratory or metabolic diseases, Nie and colleagues address a highly relevant research question from a scientific and clinical perspectives. 4 These authors have to be lauded for meticulously analysing hs-cTnT responses during a 12-wk training period to three types of high-intensity interval exercise performed on a cycle ergometer (repeated 4-min, 1-min, or 6-s "all out" sprint intervals) in young sedentary obese women. 4 It was demonstrated that hs-cTnT values that were initially elevated (>14 ng/L) in 11% of participants, both at the beginning and 1.5 weeks after the starting of the training program, were normalized after 5 and 12 weeks of training.…”

“…4 These authors have to be lauded for meticulously analysing hs-cTnT responses during a 12-wk training period to three types of high-intensity interval exercise performed on a cycle ergometer (repeated 4-min, 1-min, or 6-s "all out" sprint intervals) in young sedentary obese women. 4 It was demonstrated that hs-cTnT values that were initially elevated (>14 ng/L) in 11% of participants, both at the beginning and 1.5 weeks after the starting of the training program, were normalized after 5 and 12 weeks of training. These findings suggest adaptation of participants to exercise volume and intensity and/or possibly improved coronary endothelial function, myocardial microcirculation, and muscle metabolism which all have not been studied.…”

“…The findings by Nie and colleagues shed some light on this by clearly displaying less pronounced cTn increase after short exercise bouts, that is, high‐intensity intervals, compared to prolonged strenuous running or cycling. Moreover, they show that extremely short intervals of very high exercise intensity (6 s “all out” cycling sprints) are even better tolerated (indicated by lower cTn values) than somewhat longer (4 min and 1 min) intervals . This finding of course does not surprise since intervals are simply too short to induce myocardial mismatch between blood supply and demand that could lead alterations in myocyte permeability for cTn.…”

“…Enhanced permeability may be caused by various factors including among others myocardial stretch, oxidative stress, inflammation, acidosis, hyperthermia. As evidenced by Nie et al, exercise‐related hs‐cTnT release may diminish or even disappear after a few weeks of exercise training . Provided that attenuated cTn release parallels cardiomyocyte tolerance to intensive exercise, individually tailored training programs would be of utmost importance, as cTn release could possibly be prevented.…”

“…Only little information is available on the cTn response after short bouts of exercise like high‐intensity intervals and even less on the adaptive effects of regular training. In light of the current attractiveness of high‐intensity interval training in athletes as well as patients suffering from cardiorespiratory or metabolic diseases, Nie and colleagues address a highly relevant research question from a scientific and clinical perspectives . These authors have to be lauded for meticulously analysing hs‐cTnT responses during a 12‐wk training period to three types of high‐intensity interval exercise performed on a cycle ergometer (repeated 4‐min, 1‐min, or 6‐s “all out” sprint intervals) in young sedentary obese women .…”