The beauty of HIIT

Gotta sweat!

Gotta sweat!

HIIT is the acronym for high intensity interval training; a cardiovascular exercise strategy alternating short periods of intense anaerobic exercise with less intense recovery periods, until too exhausted to continue. The beauty of this type of exercise is its flexibility: it can be adapted to nearly any mode of exercise. Its physical and mental benefits are enormous. 

The benefits of HIIT include:

  • Improved VO2 max

  • Improved endocrine function, including insulin resistance and IGF-1 production

  • Improved calorie expenditure during and after the HIIT bout and fat loss (1)

These benefits are important to maintain health as we age. By far the most important benefit is to the endocrine system. Insulin-like growth factor (IGF-1) is the precursor to human growth hormone (HGH), and usually declines as we age. Its presence in the blood stream helps the production of collagen and repair of tissues, acting like an anabolic steroid. This hormone increases up to 700% during HIIT; (2) much more than that produced during endurance exercise bouts such as long-distance running. 

In personal training, we design fitness programs considering FITT variables: frequency, intensity, time (duration), and type of exercise (mode). (3)

For HIIT frequency, American College of Sports Medicine (ACSM) recommends two bouts of vigorous exercise per week. (4) You can also do longer, less intense bouts 2 or 3 times per week. Add some strength-building, such as resistance training two times a week and stretching after all bouts, and you will attain optimal health.

HIIT is performed as intensely as possible, and can be judge subjectively using the Modified Rate of Perceived Exertion (RPE). To use this scale, a person is asked to rate the overall feeling of difficulty at any given moment during an exercise bout. Sitting is 1, while brisk walking is a 4 and sprinting a 9 or 10. In HIIT, intensity needs to be at least an 8 on the Modified RPE scale. This may not be attainable for beginners.

HIIT time, or duration, is flexible, too. Though there is no universal HIIT session formula, these intense workouts typically last from 4 to 30 minutes, with times varying based on a participant’s current fitness level. This is the answer for time-crunched professionals: lack of time is no longer an excuse! Tabata Protocol is one popular HIIT formula: 20 seconds of intense movement with 10 seconds of active rest. Repeat 7 more times. Repeat the set two or three more times and you’re done. (5) The movement to rest ratios can be manipulated depending on the participant’s goals. Longer durations of intense effort can reduce lactate threshold while shorter ones can improve VO2max, a measure of your cardiovascular system’s ability to use oxygen. However, the differences may be insignificant for the non-professional and become a matter of personal preference.

HIIT mode is whatever you enjoy! Yoga, martial arts, ballet, speed walking/running, calisthenics, resistance training, cycling, jump rope, and swimming, can all be adapted to intervals, but not all to high intensity, (although I have seen Tabata Yoga videos on YouTube! (6)) Most group classes, such as dance and martial arts, already alternate between periods of moderately intense movement and active rest. Students watch the sequence or drill as the teacher demonstrates, then performs or practices that sequence or drill. In yoga, I ask my students to perform the vinyasa (series of connecting postures) between the asana, with effort, i.e., to give it their all. Intense effort is the key. Even if you don’t attain an 8 on the RPE, the benefits occur.

HIIT is just one of the techniques I offer my intermediate-level private yoga clients. All, though, should incorporate HIIT if they are interested in maintaining youthful vigor from increased IGF-1 as they age. Let me know if I can help you. Contact me.


  1. The Best Type of Exercise to Burn Fat.

  2. International Journal of Medical Research & Health Sciences, 2017, 6(4): 55-59

  3. ACSM’s Guidelines for Exercise Testing and Prescription, Eighth Edition, 2010. Lippincott Williams & Wiilkins. American College of Sports Medicine, Baltimore MD. Page 165.

  4. "HIIT FAQ (Frequently Asked Questions about High-Intensity Interval Training)". DOHIIT. Retrieved 2017-08-25.


  6. Tabata Yoga Workout, YouTube.