Impact of High-intensity Interval Exercise and Moderate-Intensity Continuous Exercise on the Cardiac Troponin T Level at an Early Stage of Training

We present protocol of three representative types of high intensity interval exercise and one representative type of moderate intensity continuous exercise. To observe response of circulating cardiac troponin T concentration to exercise. We recruited sedentary, overweight females, who completed a 10 day training program.

This allowed us to work in the early stage of training. And target an under researched group. The frame of cardiac troponin T release, provided by the current study, it's conditions fits with the challenge with interpreting the bell marker data clinically in the post exercise study.

The current study also provides templates of different exercise protocols with potential cardiac troponin T responses. When considering initiating exercise prescription in sedentary populations, especially for high intensity interval exercise. Start by assessing maximal oxygen uptake, or Vo2 max, of each participant by instructing them to perform a continuous incremental test on a stress testing cycle ergometer.

The participant should warm up for five minutes at 25 watts. Then begin the test by performing continuous two minute stages, starting at 50 watts, with a pedal frequency of 60RPM, until volitional exhaustion. Simultaneously, us a breath by breath metabolic analyzer to measure oxygen consumption during the exercise.

And calculate the Vo2 max based on the highest 30 second average value. During exercise record a continuous electrocardiogram via a portable ECG monitor. Ensure that all exercise tests are performed at the same time of day, in a laboratory with temperature and humidity control.

Five days after the pre-intervention assessment, instruct the particpants to commence their respective training. After a routine warmup, instruct all participants to engage in their respective exercise program on a cycle ergometer. Perform six exercise sessions over a time span of 10 days, testing for the cTnT response, on the first and sixth exercise session.

Draw venous blood samples before, and immediately after exercise. As well as three and four hours after the exercise session. For cTnT analysis, allow the blood to clot at room temperature, and centrifuge it at 3, 500 times G, for 20 minutes.

Then use an analyser to perform a quantitative measurement of the cTnT with a high sensitivity amino acid based on electrochemiluminescence. Take one milliliter of the serum, and put it into a test tube. Then insert the tube into the analyser, and press the start button.

For each exercise session, instruct participants from all four exercise groups to complete an identical 10 minute warmup at 50 to 60 percent of maximal heart rate, before exercise. After the warmup, conduct a two minute recovery period where participants remain seated, but stationary on the cycle ergometer. Direct the participant to accelerate as soon as possible at the beginning of each exercise bout to reach the intended intensity.

For the HIE protocol, the participant will repeat four minute bouts of exercise on a stress testing cycle ergometer at an intensity of 90%Vo2 max. Followed by a three minute passive recovery until the targeted 200 kilojoules of work is achieved. After setting the HIE protocol in a PC computer, count down five, four, three, two, one, go.

As the participant begins to exercise the computerized system will automatically activate. Monitor the participants revolutions per minute, to make sure it is maintained at 60. The participant should remain seated while cycling.

And their feet should be secured to the pedals with a toe clip. Verbally encourage them to give a maximal effort to exercise at the desired intensity throughout each session. For the SIE protocol, the participant will repeat one minute bouts of exercise at an intensity of 120%Vo2 max, follow by a 1.5 minute passive recovery until 200 kilojoules of work is reached.

Set the protocol and count down to indicate the participant should start to exercise which will activate the computerized system. Monitor the system to ensure the participant maintains 60 revolutions per minute. And verbally encourage them to give a maximal effort at the desired intensity.

For the RSE protocol, the participant will repeat six second all out sprints inter-spaced with nine second passive recovery periods. With a resistance of one kilogram, until the targeted 40 repetitions are achieved. Prior to starting, make sure that the participant's feet are secured to the pedals.

After setting the protocol in the computer, count down, five, four, three, two, one, go. And monitor the participant as they start to exercise. For the MCE protocol, the participant will perform continuous cycling at 60%Vo2 max until 200 kilojoules of work is achieved.

Set protocol in a PC computer and count down as previously described. Then monitor the system to make sure that the participant maintains 60 revolutions per minute. After each exercise session, instruct participants from all four exercise groups to complete an identical five minute cool down, at 20 watts.

All 47 participants completed the study, and no adverse cardiac effects were found during testing. As expected, acute exercise heart rate data at the first session, was similar to that at the sixth in all four groups. The heart rate data was highest in the RSE group, and lowest in the MCE groups.

The cTnT concentration increased, following acute exercise in all four groups. No significant difference was found in cTnT concentration among the groups, except for a smaller response at the first session in the RSE group. The appearance of higher increase than expected in cTnT in participants with recent history of acute exercise should be considered for further clinical investigation especially for repeated sprint exercise.

It remains unclear why the cTnT has similar responses in other populations, except house of young females. Which makes it worthy of further research, using the exercise protocols developed in this study.