|It takes some effort to avoid making the transition from the sofa to the ICU.|
The subjects were randomized to either a high intensity interval training or a moderate intensity steady state training group who burnt the exact same amount of energy during their workouts.
In contrast to other studies, the groups did not train at the same time. The study started in September. From September to December, the HIIT group performed high intensity interval training
- at 80-100% of their maximal heart rate during 90s-120min intervals,
- with 1-3 min pauses at 70-75% of the maximal heart rate
|Figure 1: Overview of the study protocol (translated from Kemmler. 2015).|
|Figure 2: Changes in left ventricular myocardial mass (LVMI), cardiovascular fitness (CV), intima-media thickness (IMT, associated with increased CVD risk), body fat, and lean mass (Kemmler. 2015).|
What may come as a surprise is that despite the significant improvements in fitness and metabolic disease scores (-2.06 pts vs. -1.6 pts with HIIT vs. MIST, respectively), the amount of fat lost was more pronounced in the MIST group; and that in spite of the fact that they performed only 5% of their training at the maximal heart frequency, 10% at high intensities and the vast majority of exercise, i.e. 85%, at a moderate exercise intensity. In view of the fact that the design of the study required that all participants expended the same amount of energy, it's quite interesting that the subjects in the MIST study burned more body fat than the subjects in the HIIT study. In the absence of a strictly controlled energy intake, it's yet no reliable evidence that would disprove the rule that HIIT is - specifically for leaner folks - the more effective fat burner. The result of the study at hand should thus not be overrated.
Isn't high intensity training dangerous for those with heart disease? It's certainly not useful for everyone, but scientific evidence suggests that performing at high individual heart rates is beneficial and safe for cardiac rehabilitation patients (Beniamini. 1999; Warburton. 2005; Tinkham. 2014)
|Figure 2: Endothelial function measured as FMD (left); maximal oxygen uptake (right) before and after 12-week high intensity interval or moderate intensity steady state exercise in patients with heart failure (Wisløff . 2007)|
Yet in spite of the fact that the researchers highlight that their results would have "important implications for exercise training in rehabilitation programs" - the impact on the real world prescriptions in such programs is negligible.,
- Beniamini, Yael, et al. "High-intensity strength training of patients enrolled in an outpatient cardiac rehabilitation program." Journal of Cardiopulmonary Rehabilitation and Prevention 19.1 (1999): 8-17.
- Kemmler, Wolfgang, et al. "Hoch-versus moderat-intensive Laufbelastung–Einfluss auf kardio-metabolische Risikogrößen bei untrainierten Männern." DMW-Deutsche Medizinische Wochenschrift 140.01 (2015): e7-e13.
- Tanasescu, Mihaela, et al. "Exercise type and intensity in relation to coronary heart disease in men." Jama 288.16 (2002): 1994-2000.
- Tinkham, Michelle. "Health Promotion in Cardiac Rehabilitation Patients through the Use of a High-Intensity Interval Training Protocol." World Journal of Cardiovascular Diseases 4.10 (2014): 493.
- Warburton, Darren ER, et al. "Effectiveness of high-intensity interval training for the rehabilitation of patients with coronary artery disease." The American journal of cardiology 95.9 (2005): 1080-1084.
- Wisløff, Ulrik, et al. "Superior cardiovascular effect of aerobic interval training versus moderate continuous training in heart failure patients a randomized study." Circulation 115.24 (2007): 3086-3094.