High-intensity interval training
High-intensity interval training (HIIT), also called High-Intensity Intermittent Exercise (HIIE) or sprint interval training, is an enhanced form of interval training, an exercise strategy alternating periods of short intense anaerobic exercise with less-intense recovery periods. HIIT is an effective form of cardiovascular exercise. Usual HIIT sessions may vary from 9–20 minutes. These short, intense workouts provide improved athletic capacity and condition, improved glucose metabolism, and improved fat burning.
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[edit] Procedure
A HIIT session consists of a warm up period of exercise, followed by six to ten repetitions of high intensity exercise, separated by medium intensity exercise, and ending with a period of cool down exercise. The high intensity exercise should be done at near maximum intensity. The medium exercise should be about 50% intensity. The number of repetitions and length of each depends on the exercise. The goal is to do at least six cycles, and to have the entire HIIT session last at least fifteen minutes and not more than twenty.
The original protocol set 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.
HIIT is considered to be an excellent way to maximize a workout that is limited on time.[1]
[edit] Tabata Method
A popular regimen based on a 1996 study[2] uses 20 seconds of ultra-intense exercise (at an intensity of about 170% of VO2max) followed by 10 seconds of rest, repeated continuously for 4 minutes (8 cycles). Tabata called this the IE1 protocol.[3] In the original study, athletes using this method trained 4 times per week, plus another day of steady-state training, and obtained gains similar to a group of athletes who did steady state (70% VO2max) training 5 times per week. The steady state group had a higher VO2max at the end (from 52 to 57 ml/kg/min), but the Tabata group had started lower and gained more overall (from 48 to 55 ml/kg/min). Also, only the Tabata group had gained anaerobic capacity benefits.
[edit] Little Method
An alternative regimen based on a 2009 study[4] uses 60 seconds of intense exercise (at 95% of VO2max) followed by 75 seconds of rest, repeated for 8–12 cycles. Subjects using this method trained 3 times per week, and obtained gains similar to what would be expected from subjects who did steady state (50–70% VO2max) training for five times per week. While still a demanding form of training, this exercise protocol could be used by the general public with nothing more than an average exercise bike.
[edit] Benefits
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[edit] Aerobic benefits
Studies by Tabata,[2] Tremblay[5] and others have explored the effectiveness of this method compared to traditional endurance training methods. A study by Gibala et al.[6] demonstrated 2.5 hours of sprint interval training produced similar biochemical muscle changes to 10.5 hours of endurance training and similar endurance performance benefits. According to a study by King,[7] HIIT increases the resting metabolic rate (RMR) for the following 24 hours due to excess post-exercise oxygen consumption, and may improve maximal oxygen consumption (VO2 max) more effectively than doing only traditional, long aerobic workouts.[8][9][10][11] Tabata's 1997 study concluded that "intermittent exercise defined by the IE1 protocol may tax both the anaerobic and aerobic energy releasing systems almost maximally."[3]
High-intensity interval training has also been shown to improve athletic performance. For already well-trained athletes, improvements in performance become difficult to attain and increases in training volume can potentially yield no improvements. Previous research would suggest that, for athletes who are already trained, improvements in endurance performance can be achieved through high-intensity interval training. A recent study by Driller[12] showed an 8.2 second improvement in 2000m rowing time following 4 weeks of HIIT in well-trained rowers. This equates to a significant 2% improvement after just 7 interval training sessions. The interval training used by Driller and colleagues involved 8 x 2.5 minute work bouts at 90% of vVO2max, with individualized recovery intervals between each work bout.
[edit] Metabolic benefits
Long aerobic workouts have been promoted as the best method to reduce fat, as fatty acid utilization usually occurs after at least 30 minutes of training.[citation needed] HIIT is somewhat counterintuitive in this regard, but has nonetheless been shown to burn fat more effectively.[13][5] There may be a number of factors that contribute to this, including an increase in RMR. HIIE also significantly lowers insulin resistance and causes skeletal muscle adaptations that result in enhanced skeletal muscle fat oxidation and improved glucose tolerance.[13]
Recently it has been shown that two weeks of HIIT can substantially improve insulin action in young healthy men.[14] Similarly, in young women, HIIE three times per week for 15 weeks compared to the same frequency of SSE exercise was associated with significant reductions in total body fat, subcutaneous leg and trunk fat, and insulin resistance.[15] HIIT may therefore represent a viable method for prevention of type-2 diabetes.
[edit] Cardiovascular disease
A 2011 study by Buchan et al. assessing the effect of HIIT on cardiovascular disease markers in adolescents reported that "brief, intense exercise is a time efficient means for improving CVD risk factors in adolescents".[16]
[edit] See also
[edit] References
- ^ Van Dusen, Allison (October 20, 2008). "Ten ways to get more from your workout". Forbes. http://www.forbes.com/2008/10/20/exercise-workout-shorter-forbeslife-cx_avd_1020health.html. Retrieved December 14, 2008.
- ^ a b Tabata I, Nishimura K, Kouzaki M, et al. (1996). "Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max". Med Sci Sports Exerc 28 (10): 1327–30. doi:10.1097/00005768-199610000-00018. PMID 8897392.
- ^ a b Tabata I, Irisawa K, Kouzaki M, Nishimura K, Ogita F, Miyachi M (March 1997). "Metabolic profile of high intensity intermittent exercises". Med Sci Sports Exerc 29 (3): 390–5. PMID 9139179.
- ^ Little, Jonathan P; Adeel S. Safdar, Geoffrey P. Wilkin, Mark A. Tarnopolsky, and Martin J. Gibala (2009). "A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms". J Physiol 588 (Pt 6): 1011–22. doi:10.1113/jphysiol.2009.181743. PMC 2849965. PMID 20100740. http://jp.physoc.org/content/early/2010/01/20/jphysiol.2009.181743.abstract.
- ^ a b Tremblay A, Simoneau JA, Bouchard C (1994). "Impact of exercise intensity on body fatness and skeletal muscle metabolism". Metab. Clin. Exp. 43 (7): 814–8. doi:10.1016/0026-0495(94)90259-3. PMID 8028502.
- ^ Gibala, Martin J; Jonathan P. Little, Martin van Essen, Geoffrey P. Wilkin, Kirsten A. Burgomaster, Adeel Safdar, Sandeep Raha and Mark A. Tarnopolsky (September 15 2006). "Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance". J Physiol 575 (3): 901–911. doi:10.1113/jphysiol.2006.112094. PMC 1995688. PMID 16825308. http://jp.physoc.org/cgi/content/short/575/3/901. Retrieved 2008-07-23.
- ^ East Tennessee State University Thesis
- ^ Smith TP, Coombes JS, Geraghty DP (2003). "Optimising high-intensity treadmill training using the running speed at maximal O(2) uptake and the time for which this can be maintained". Eur. J. Appl. Physiol. 89 (3–4): 337–43. doi:10.1007/s00421-003-0806-6. PMID 12736843.
- ^ Rozenek R, Funato K, Kubo J, Hoshikawa M, Matsuo A (2007). "Physiological responses to interval training sessions at velocities associated with VO2max". J Strength Cond Res 21 (1): 188–92. doi:10.1519/R-19325.1. PMID 17313282.
- ^ Helgerud J, Høydal K, Wang E, et al. (2007). "Aerobic high-intensity intervals improve VO2max more than moderate training". Med Sci Sports Exerc 39 (4): 665–71. doi:10.1249/mss.0b013e3180304570. PMID 17414804.
- ^ Esfarjani F, Laursen PB (2007). "Manipulating high-intensity interval training: effects on VO2max, the lactate threshold and 3000 m running performance in moderately trained males". J Sci Med Sport 10 (1): 27–35. doi:10.1016/j.jsams.2006.05.014. PMID 16876479.
- ^ Driller Matthew, Fell James, Gregory John, Shing Cecilia, Williams Andrew (2009). "The effects of high-intensity interval training in well-trained rowers". International Journal of Sports Physiology and Performance 4: 1. http://www.humankinetics.com/IJSPP/viewarticle.cfm?aid=16868.
- ^ a b Boutcher SH (2011). "High-intensity intermittent exercise and fat loss". J Obes 2011: 868305. doi:10.1155/2011/868305. PMC 2991639. PMID 21113312. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2991639.
- ^ Babraj J, Vollaard N, Keast C, Guppy F, Cottrell G, Timmons J (2009). "Extremely short duration high intensity interval training substantially improves insulin action in young healthy males". BMC Endocrine Disorders 9: 3. doi:10.1186/1472-6823-9-3. PMC 2640399. PMID 19175906. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2640399.
- ^ Trapp EG, Chisholm DJ, Freund J, Boutcher SH (April 2008). "The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women". Int J Obes (Lond) 32 (4): 684–91. doi:10.1038/sj.ijo.0803781. PMID 18197184.
- ^ Buchan DS, Ollis S, Young JD, et al. (2011). "The effects of time and intensity of exercise on novel and established markers of CVD in adolescent youth". Am. J. Hum. Biol. 23 (4): 517–26. doi:10.1002/ajhb.21166. PMID 21465614.
[edit] External links
- Tremblay A, Simoneau JA, Bouchard C (1994). "Impact of Exercise Intensity on Body Fatness and Skeletal Muscle Metablism". Metabolism 43 (7): 814–818. doi:10.1016/0026-0495(94)90259-3. PMID 8028502.
- Everything you need to know about HIIT
- Sprint Training HIIT vs LMICT
- A Primer On HIIT – High Intensity Interval Training
- Effects of High-intensity Training on Performance and Physiology of Endurance Athletes (.htm format) (.doc format)
- Tabata I. et. al. (1996). "Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max". Med Sci Sports Exerc. 28 (10): 1327–30. doi:10.1097/00005768-199610000-00018. PMID 8897392.
- How 1-Minute Intervals Can Improve Your Health by Gretchen Reynolds in the New York Times, 2012-02-15
- Physiological adaptations to low-volume, high-intensity interval training in health and disease. abstract from the Journal of Physiology, 2012-01-30, reporting on a study by Gibala MJ, Little JP, Macdonald MJ, and Hawley JA from McMasters University.
- Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans Journal of Physiology, 2008-01-01, by Kirsten A Burgomaster, Krista R Howarth, Stuart M Phillips, Mark Rakobowchuk, Maureen J MacDonald, Sean L McGee, and Martin J Gibala. doi:10.1113/jphysiol.2007.142109, pdf version.
