To elucidate whether that's a reasonable and, more importantly, sufficient (meaning: "Is the increased energy expenditure high enough to explain the fat loss, even if the steady state exercise consumes more energy and fat on total?") explanation for the previously mentioned advantages, researchers from the Healthy Lifestyles Research Center at the Arizona State University conducted a study to compare the EPOC response to the three most common forms of aerobic training: high intensity interval exercise (HIE), sprint interval exercise (SIE), and steady state exercise (SSE).
Ten recreationally active males (age 24 ± 4 y) participated in this randomized crossover study. On separate days, subjects completed a resting control trial and three exercise conditions on a cycle ergometer:
- HIE (four 4-min intervals at 95% HRpeak, separated by three min of active recovery); and
- SIE (six 30-s Wingate sprints, separated by four min of active recovery); and
- SSE (30 min at 80% of peak heart rate (HRpeak)).
|Figure 1: Oxygen consumption and respiratory exchange ratio (higher numbers = higher carbohydrate to fat oxidation ratio) during the first three hours after exercise (Tucker. 2016).|
There's room for "cardio": Even though it is not popular, these days, it would be wrong to assume that classic steady state training is always the inferior choice. For someone who's killing it in the gym regularly, the additional HIIT training may in fact be too much of a sympathetic stimulus. The "boring" classic "cardio" training, on the other hand, is predominantly parasympathetic, which is why walking on an incline treadmill may eventually be a better complement to your 4-5 resistance training sessions per week than HIIT cycling or sprinting.It is thus not really surprising that both, the complete 3-h EPOC and the total net EE after exercise were not extremely different and that that 3-h EPOC and total net EE after exercise were higher (p=0.01) for SIE (22.0 ± 9.3 L; 110 ± 47 kcal) compared to SSE (12.8 ± 8.5 L; 64 ± 43 kcal).
|Figure 2: The total O2 consumption (and thus fat oxidation) and energy expenditure during the workout and the 3h thereafter shows that steady state exercise burns more fat and energy than any of the two HIIT regimen (Tucker. 2016).|
- Sevits, Kyle J., et al. "Total daily energy expenditure is increased following a single bout of sprint interval training." Physiological reports 1.5 (2013): e00131.
- Tucker, Wesley J., Siddhartha S. Angadi, and Glenn A. Gaesser. "Excess postexercise oxygen consumption after high-intensity and sprint interval exercise, and continuous steady-state exercise." The Journal of Strength & Conditioning Research (2016).