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What is HIIT?


What is High Intensity Interval Training, Or HIIT?

            •  High-intensity interval training (HIIT), also called high-intensity intermittent exercise (HIIE) or sprint interval training (SIT), is an enhanced form of interval training.  As an exercise strategy combining alternating periods of short intense anaerobic exercise with less intense recovery periods, HIIT is an effective form of cardiovascular exercise.

How long is a HIIT workout?

            • Usual HIIT sessions may vary from 4–30 minutes. These short, intense workouts provide improved athletic capacity and condition, improved glucose metabolism and improved fat burning.

            • The entire HIIT session may last between four and thirty minutes, meaning that it is considered to be an excellent way to maximize a workout that is limited on time. Use of a clock or timer helps to keep accurate times, proper metrics, number of rounds and intensity.

What does a HIIT workout consist of?

            • A HIIT session often consists of a warm up period of exercise, followed by three to ten repetitions of high intensity exercise, separated by medium intensity exercise for recovery and ending with a period of cool-down exercise. The high intensity exercise should be done at near maximum intensity and the medium exercise should be about 50% intensity. The number of repetitions and length of each depends on the exercise, but may be as little as three repetitions with just 20 seconds of intense exercise.

What should my HIIT workout look like?

            • There is no specific formula to HIIT. In other words, intensity is determined solely by the individual and their athletic capacity. Maximum effort is the determining factor on the effectiveness of a HIIT regimen. Depending on one's level of cardiovascular development, the moderate-level intensity can be as slow as walking. A common formula involves a 2:1 ratio of work to recovery periods, for example, 30–40 seconds of hard sprinting alternated with 15–20 seconds of jogging or walking.


            • Instead of spending hours at the gym, you can do high intensity interval training workouts at home, during travel or outdoors. Workouts don’t need much space, require little to no equipment and can be completed in minutes, not hours.

            • Scientific research has found that HIIT outperforms conventional aerobic endurance exercise. HIIT provides health benefits you cannot get from regular exercise. High intensity exercise regimes provide a huge boost in production of human growth hormone (HGH), which has been dubbed the “fitness hormone” because of its profound health and anti-aging properties. During HIIT sessions the glucagon hormone is released to help regulate blood sugar levels and control the insulin hormone which in turn causes fat to be used as energy instead of stored.

Further Research

            • Here is a compilation of some of the best peer-reviewed scientific research on HIIT as well as SIT.  This also includes Tabata Training as well as some of the other less well known HIIT regimes and protocols.

Bartlett, J.D. et al. (2011). High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: implications for exercise adherence. Journal of Sports Sciences, 29, 6, 547-553.

Interval training in the fed or fasted state improves body composition and muscle oxidative capacity in overweight women.
Gillen JB, Percival ME, Ludzki A, Tarnopolsky MA, Gibala MJ.
Obesity (Silver Spring). 2013 Feb 1. doi: 10.1002/oby.20379. [Epub ahead of print] PMID: 23723099 [PubMed – as supplied by publisher]

Endurance and sprint benefits of high-intensity and supramaximal interval training.
Cicioni-Kolsky D, Lorenzen C, Williams MD, Kemp JG.
Eur J Sport Sci. 2013 May;13(3):304-11. doi: 10.1080/17461391.2011.606844. Epub 2011 Dec 9.
PMID: 23679147 [PubMed – in process]

High-Intensity Intermittent Exercise – Methodological and Physiological Aspects.
Tschakert G, Hofmann P.
Int J Sports Physiol Perform. 2013 Jun 24. [Epub ahead of print] PMID: 23799827 [PubMed – as supplied by publisher]

Improvements in exercise performance with high-intensity interval training coincide with an increase in skeletal muscle mitochondrial content and function.
Jacobs RA, Flück D, Bonne TC, Bürgi S, Christensen PM, Toigo M, Lundby C.
J Appl Physiol. 2013 Jun 20. [Epub ahead of print] PMID: 23788574 [PubMed – as supplied by publisher]

Nutritional strategies to support adaptation to high-intensity interval training in team sports.
Gibala MJ.
Nestle Nutr Inst Workshop Ser. 2013;75:41-9. doi: 10.1159/000345817. Epub 2013 Apr 16.
PMID: 23765349 [PubMed – in process]

Low- and high-volume of intensive endurance training significantly improves maximal oxygen uptake after 10-weeks of training in healthy men.
Tjønna AE, Leinan IM, Bartnes AT, Jenssen BM, Gibala MJ, Winett RA, Wisløff U.
PLoS One. 2013 May 29;8(5):e65382. doi: 10.1371/journal.pone.0065382. Print 2013.
PMID: 23734250 [PubMed – in process] Free PMC Article

High intensity interval training vs. high-volume running training during pre-season conditioning in high-level youth football: a cross-over trial.
Faude O, Schnittker R, Schulte-Zurhausen R, Müller F, Meyer T.
J Sports Sci. 2013 May 31. [Epub ahead of print] PMID: 23725006 [PubMed – as supplied by publisher]

Efficacy of acute high-intensity interval training in lowering glycemia in patients with type 2 diabetes: diabetes em movimento(r) pilot study.
Mendes R, Sousa N, Garrido N, Rocha P, Themudo Barata José L, Reis Victor M.
Br J Sports Med. 2013 Jul;47(10):e3. doi: 10.1136/bjsports-2013-092558.19.
PMID: 23757644 [PubMed – in process]

Applying the Critical Velocity Model for an Off-Season Interval Training Program.
Clark IE, West B, Reynolds S, Murray SR, Pettitt RW.
J Strength Cond Res. 2013 Mar 8. [Epub ahead of print] PMID: 23478481 [PubMed – as supplied by publisher]

Evidence based exercise – clinical benefits of high intensity interval training.
Shiraev T, Barclay G.
Aust Fam Physician. 2012 Dec;41(12):960-2.
PMID: 23210120 [PubMed – in process] Free Article

High intensity interval exercise training in overweight young women.
Sijie T, Hainai Y, Fengying Y, Jianxiong W.
J Sports Med Phys Fitness. 2012 Jun;52(3):255-62.
PMID: 22648463 [PubMed – indexed for MEDLINE]

Effect of high-intensity interval training on cardiovascular function, VO2max, and muscular force.
Astorino TA, Allen RP, Roberson DW, Jurancich M.
J Strength Cond Res. 2012 Jan;26(1):138-45. doi: 10.1519/JSC.0b013e318218dd77.
PMID: 22201691 [PubMed – indexed for MEDLINE]

High-intensity interval training vs. repeated-sprint training in tennis.
Fernandez-Fernandez J, Zimek R, Wiewelhove T, Ferrauti A.
J Strength Cond Res. 2012 Jan;26(1):53-62. doi: 10.1519/JSC.0b013e318220b4ff.
PMID: 21904233 [PubMed – indexed for MEDLINE]

High-intensity interval training improves VO(2peak), maximal lactate accumulation, time trial and competition performance in 9-11-year-old swimmers.
Sperlich B, Zinner C, Heilemann I, Kjendlie PL, Holmberg HC, Mester J.
Eur J Appl Physiol. 2010 Nov;110(5):1029-36. doi: 10.1007/s00421-010-1586-4. Epub 2010 Aug 4.
PMID: 20683609 [PubMed – indexed for MEDLINE] Free PMC Article

The response of interleukin-6 and soluble interleukin-6 receptor isoforms following intermittent high intensity and continuous moderate intensity cycling.
Leggate M, Nowell MA, Jones SA, Nimmo MA.
Cell Stress Chaperones. 2010 Nov;15(6):827-33. doi: 10.1007/s12192-010-0192-z. Epub 2010 Apr 16.
PMID: 20396982 [PubMed – indexed for MEDLINE] Free PMC Article

The effects of a pre-workout supplement containing caffeine, creatine, and amino acids during three weeks of high-intensity exercise on aerobic and anaerobic performance.
Smith AE, Fukuda DH, Kendall KL, Stout JR.
J Int Soc Sports Nutr. 2010 Feb 15;7:10. doi: 10.1186/1550-2783-7-10.
PMID: 20156347 [PubMed] Free PMC Article

The effects of four weeks of creatine supplementation and high-intensity interval training on cardiorespiratory fitness: a randomized controlled trial.
Graef JL, Smith AE, Kendall KL, Fukuda DH, Moon JR, Beck TW, Cramer JT, Stout JR.
J Int Soc Sports Nutr. 2009 Nov 12;6:18. doi: 10.1186/1550-2783-6-18.
PMID: 19909536 [PubMed] Free PMC Article

Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women.
Talanian JL, Galloway SD, Heigenhauser GJ, Bonen A, Spriet LL.
J Appl Physiol. 2007 Apr;102(4):1439-47. Epub 2006 Dec 14.
PMID: 17170203 [PubMed – indexed for MEDLINE] Free Article

Impact of exercise intensity on body fatness and skeletal muscle metabolism.
Tremblay A, Simoneau JA, Bouchard C.
Metabolism. 1994 Jul;43(7):814-8.
PMID: 8028502 [PubMed – indexed for MEDLINE]

Metabolic profile of high intensity intermittent exercises.
Tabata I, Irisawa K, Kouzaki M, Nishimura K, Ogita F, Miyachi M.
Med Sci Sports Exerc. 1997 Mar;29(3):390-5.
PMID: 9139179 [PubMed – indexed for MEDLINE]

Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max.
Tabata I, Nishimura K, Kouzaki M, Hirai Y, Ogita F, Miyachi M, Yamamoto K.
Med Sci Sports Exerc. 1996 Oct;28(10):1327-30.
PMID: 8897392 [PubMed – indexed for MEDLINE]

In addition I have added links to various sites if you would like to get more information concerning High Intensity Interval Training.      

  1. https://seeingtheice.wordpress.com/2010/11/04/mike-boyle-on-hiit
  2. http://www.strengthcoach.com/public/1766.cfm
  3. http://www.unifiedstream.com/the-science-behind-high-intensity-interval-training/
  4. http://en.wikipedia.org/wiki/High-intensity_interval_training
  5. http://www.strengthcoach.com/public/1766.cfm
  1. http://www.womenshealthmag.com/fitness/hiit-workout
  2. http://www.shapefit.com/exercise/what-is-crossfit.html
  3. http://www.wpi.edu/Pubs/E-project/Available/E-project-030112-113016/unrestricted/Final_Write-Up.pdf
  4. http://www.sciencedaily.com/releases/2010/03/100311123639.htm
  5. http://www.usatoday.com/story/news/nation/2013/10/24/fitness-trends-high-intensity-workout/3009699/