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Do you have to do Cardio to Improve your Cardio?


Take Home Points on HIIT

  1. HIIT likely an effective mechanism to improve mitochondrial density.
  2. HIIT doesn’t directly lose weight, but can increase work capacity and future weight loss.
High-intensity interval training (HIIT)  is the latest and

greatest form of training. Now, many claim to understand and prescribe HIIT, but at the COR boot camps and with our COR personal training, we utilize HIIT safely and intelligently. No matter if you are an Olympic level swimmer or someone seeking weight loss, HIIT has some allure, but don’t get lost in the hype! HIIT has it’s benefits, but isn’t the Rosetta stone!

What is HIIT?

The typical HIIT workout utilizes the Tabata protocol, which is simply 8 x :20 of a something fast with :10 rest in between each set.

A recent study looked at the use of HIIT, specifically with the “Tabata style” form of training: 4×4 training sessions of 8×20 s intervals separated by 10 s rest. Each subject cycled on a bicycle ergomemter, with a high resistance at 170% of the individuals peak aerobic power.

The results found this form of training is extremely effective, as 19%, 14%, and 13% increases in VO2peak, peak aerobic performance, and mean power during the Wingate test resulted in only 43 minutes of actual exercise across a 4-week time span.

Simply put, you don’t have to do “cardio” training to improve your cardiovascular fitness. However, these improvements are likely peripheral improvements, not centrally mediated, as proposed by Ma (2013).

What does HIIT do?

Now, in this study citrate synthase didn’t reach a statistically

significant improvement, but the increase in mitochondrial proteins (COX I and IV) still allows an increase in fatty acid oxidation during exercise. Unfortunately, only doing HIIT to lose weight (specifically body fat) is likely unwarranted, as the calorie expenditure is too low. However, HIIT is likely a superior mitochondiral builder, which will ramp PGC-1α, increase your mitochondiral and oxidative capacity. This will allow you to run further or faster and likely burn more calories during a future workout (a secondary method for weight loss).

This makes HIIT an essential aspect for oxidative improvement, work capacity increases, and subsequent weight loss!


    1. Ma, J. K., Scribbans, T. D., Edgett, B. A., Boyd, J. C., Simpson, C. A., Little, J. P., & Gurd, B. J. (2013). Extremely low-volume, high-intensity interval training improves exercise capacity and increases mitochondrial protein content in human skeletal muscle. Open Journal of Molecular and Integrative Physiology, 3, 202.
    2. Wu, Z., Puigserver, P., Andersson, U., Zhang, C., Adelmant, G., Mootha, V., … & Spiegelman, B. M. (1999). Mechanisms controlling mitochondrial biogenesis and respiration through the thermogenic coactivator PGC-1. Cell, 98(1), 115-124.

     Dr. John, DPT, CSCS