ArticlePDF Available

Evidence based exercise: Clinical benefits of high intensity interval training

Authors:

Abstract

Background: Aerobic exercise has a marked impact on cardiovascular disease risk. Benefits include improved serum lipid profiles, blood pressure and inflammatory markers as well as reduced risk of stroke, acute coronary syndrome and overall cardiovascular mortality. Most exercise programs prescribed for fat reduction involve continuous, moderate aerobic exercise, as per Australian Heart Foundation clinical guidelines. Objective: This article describes the benefits of exercise for patients with cardiovascular and metabolic disease and details the numerous benefits of high intensity interval training (HIIT) in particular. Discussion: Aerobic exercise has numerous benefits for high-risk populations and such benefits, especially weight loss, are amplified with HIIT. High intensity interval training involves repeatedly exercising at a high intensity for 30 seconds to several minutes, separated by 1-5 minutes of recovery (either no or low intensity exercise). HIT is associated with increased patient compliance and improved cardiovascular and metabolic outcomes and is suitable for implementation in both healthy and 'at risk' populations. Importantly, as some types of exercise are contraindicated in certain patient populations and HIIT is a complex concept for those unfamiliar to exercise, some patients may require specific assessment or instruction before commencing a HIIT program.
clinical
Evidence based exercise
Clinical benefits of high intensity interval training
Tim Shiraev
Gabriella Barclay
mortality.5–10 Exercise has been shown to be
an important additional strategy to a weight
loss program.11 However, in Australia, nearly
40% of males and 60% of females carry out
insufficient daily physical activity.12
Aerobic exercise has a marked impact on
cardiovascular disease risk. Benefits include
improved serum lipid profiles, blood pressure
and inflammatory markers as well as reduced
risk of stroke, acute coronary syndrome and
overall cardiovascular mortality.13–19 Additionally,
aerobic exercise is effective in the prevention and
management of insulin resistance and T2DM.20,21
A recent meta-analysis looking at the effect of
different levels of light or moderate physical activity
on all cause mortality demonstrated that 30 minutes
of moderate exercise five times per week (the basis
of most exercise prescription guidelines22) reduced
all cause mortality by 19% versus no activity.23
Importantly, as light or moderate aerobic exercise
can be carried out in an incidental manner, it is
potentially accessible and nondisruptive to most of
the population.
High intensity interval
training
Many exercise programs prescribed for fat reduction
involve continuous, moderate aerobic exercise
(CME), as per Australian Heart Foundation clinical
guidelines.22 However, such exercise programs
have been shown to fail to result in significant fat
loss.13,24
High intensity interval training (HIIT) involves
repeatedly exercising at a high intensity for 30
seconds to several minutes, separated by 1–5
minutes of recovery (either no or low intensity
exercise).25 The most common HIIT intervention
used in studies is the Wingate Protocol developed
in the 1970s.26 This involves 30 seconds of cycling
at maximum effort (at an intensity of over 90% of
maximal oxygen uptake, also known as 90% of VO2
Obesity rates in Australia are among
the highest in the world,1 with one in 4
adults being obese.2 Obesity increases
the risk of coronary heart disease, type
2 diabetes mellitus (T2DM) and stroke,
three of the top five causes of burden of
disease and injury in Australia.2 Dietary
modification is the mainstay of any
weight loss program3,4 and has been
shown to improve cardiovascular and
metabolic risk factors including blood
pressure, lipids, serum glucose, glycated
haemoglobin (HbA1c) and insulin
levels as well as reducing risk of acute
coronary syndromes, stroke and all cause
Background
Aerobic exercise has a marked impact on cardiovascular disease risk. Benefits
include improved serum lipid profiles, blood pressure and inflammatory
markers as well as reduced risk of stroke, acute coronary syndrome and overall
cardiovascular mortality. Most exercise programs prescribed for fat reduction
involve continuous, moderate aerobic exercise, as per Australian Heart
Foundation clinical guidelines.
Objective
This article describes the benefits of exercise for patients with cardiovascular and
metabolic disease and details the numerous benefits of high intensity interval
training (HIIT) in particular.
Discussion
Aerobic exercise has numerous benefits for high-risk populations and such
benefits, especially weight loss, are amplified with HIIT. High intensity interval
training involves repeatedly exercising at a high intensity for 30 seconds to
several minutes, separated by 1–5 minutes of recovery (either no or low intensity
exercise). HIT is associated with increased patient compliance and improved
cardiovascular and metabolic outcomes and is suitable for implementation in
both healthy and ‘at risk’ populations. Importantly, as some types of exercise are
contraindicated in certain patient populations and HIIT is a complex concept for
those unfamiliar to exercise, some patients may require specific assessment or
instruction before commencing a HIIT program.
Keywords
exercise therapy; risk factors; body weight
960
Reprinted from AUSTRALIAN FAMILY PHYSICIAN VOL. 41, NO. 12, DECEMBER 2012
clinicalEvidence based exercise – clinical benefits of high intensity interval training
max) separated by 4 minutes of recovery, repeated
4–6 times per session, with three sessions
per week.25,27 This results in only 2–3 minutes
of exercise at maximum intensity and 15–25
minutes of low intensity exercise per session,
making it a time efficient method of exercise. Less
demanding protocols may be utilised for sedentary,
overweight patients, which is important to
remember considering the target patient population
for exercise as prevention and management of
cardiovascular and metabolic disease.
HIIT vs continuous
moderate exercise
High intensity interval training has been shown to
significantly reduce subcutaneous fat, especially
abdominal fat,27 as well as total body mass,28,29
and to improve VO2 max (a marker of physical
fitness)30 and insulin sensitivity.31 In comparison
with CME, HIIT burns more calories and increases
postexercise fat oxidation and energy expenditure
more than steady-state exercise.32 Further, HIIT
decreased total cholesterol and LDL-cholesterol,
while increasing HDL-cholesterol33 and VO2 max32
more than CME. Interestingly, in a 2008 study,
fat loss was significantly increased after HIIT,
while fat loss did not change in CME patients
versus controls,31 ie. there was no difference in
fat loss between subjects carrying out CME and
the inactive subjects. In a study that highlights
the efficacy of HIIT, subjects carrying out HIIT
demonstrated improvements in endothelial
function, VO2 max, body mass index (BMI), body
fat percentage, blood pressure and glucose
regulation, more so than a group receiving dietary
and psychological advice in addition to CME.29
Perhaps most importantly, increased exercise
energy expenditure (such as with HIIT) as assessed
by metabolic equivalents (METs) has been shown to
result in a reduced risk of cardiovascular events in
both males18 and females,17 and decrease all cause
mortality.34 However, long term studies are needed
to specifically assess the effect of HIIT on overall
mortality.
HIIT effects in high risk
populations
In patients with cardiovascular disease, HIIT was
shown to be superior to CME in reducing blood
pressure,35 improving endothelial function,35–37 lipid
profiles,38 VO2 max,38 left ventricular37 and overall
myocardial function,35 as well as reversing left
ventricular remodelling in heart failure patients.37
Patients with metabolic syndrome who carry out
HIIT have been demonstrated to have improved
endothelial function, insulin signalling, blood
glucose and lipogenesis.29
Studies carried out in T2DM patients
demonstrated reduced blood glucose and increased
mitochondrial capacity and GLUT4 expression after
only 2 weeks of three 20 minute sessions of HIIT
per week,39 and have been shown to significantly
improve glucose tolerance at 6 months with no
such changes in CME subjects.40
Importantly, HIIT programs are not only
effective, but are also safe. HIIT has been used
effectively in patients with diabetes,39 stable
angina,41 heart failure37 and after myocardial
infarct,38 as well as postcardiac stenting42 and
coronary artery grafting.43
Further research is still required into the effect
of HIIT versus CME in cohorts with cardiometabolic
diseases, especially observation of long term
outcomes. Similarly, elucidation of the efficacy
of HIIT in certain patient populations is needed,
such as in those who have recovered from a
cerebrovascular event or in those suffering from
peripheral arterial disease.
Patient perspectives
A common reason given for not exercising is time
constraints,44 and long term adherence to exercise
programs is often less than 50% at 6 months.45 HIIT
allows equal or improved outcomes for markedly
less time investment and has the potential to be
associated with higher rates of adherence46 due
to the varied protocol leading to less boredom,29,47
although this remains controversial.48 In one study,
similar changes were seen over a 6 week period
in both HIIT subjects and CME subjects, although
HIIT subjects performed only 20% of the exercise
duration performed by the CME group,49 making it
an extremely efficient intervention.
Potential disadvantages of
HIIT
Injuries are often a concern when beginning any
exercise program (particularly one such as HIIT),
especially in elderly and sedentary patients. While
musculoskeletal injuries may occur, they are not
more common in groups performing HIIT50 versus
other forms of exercise and can be minimised
with careful selection of exercise equipment,
for example cycling instead of walking. A recent
systematic review demonstrated no cardiac or
other potentially lethal events across seven HIIT
studies in patients with coronary artery disease,51
suggesting HIIT is very safe when performed in a
controlled environment, although prescription of
such exercise must be considered on an individual
patient basis.
Due to the extreme energy expenditure
required in the interval phases of HIIT, high levels
of motivation are required. While effective in
controlled trials, and perhaps associated with
higher adherence levels (as discussed above),
studies to assess long term adherence rates to HIIT
are still needed.
Importantly, as some types of exercise are
contraindicated in certain patient populations52
and because HIIT is a complex concept for those
unfamiliar to exercise, some patients may require
specific assessment or instruction in HIIT from an
exercise physiologist or physiotherapist.
Conclusion
High intensity interval training has been shown to
have numerous clinical benefits for both healthy
and ‘at risk’ populations. General practitioners
are encouraged to discuss with their patients the
concept of ‘evidence based exercise’ and using HIIT
as part of their exercise program.
Authors
Tim Shiraev BSc(Hons) is a final year medical
student, University of Notre Dame, School of
Medicine, Sydney, New South Wales. timothy.
shiraev1@my.nd.edu.au
Gabriella Barclay BSc(Nutrition)(Hons), is a dieti-
cian, St Vincent’s Hospital, Sydney, New South
Wales.
Conflict of interest: none declared.
References
1. International Obesity Taskforce. Obesity prevalence
worldwide. 2010. Available at www.iaso.org/iotf/
obesity/ [Accessed 14 August 2012].
2. Australian Institute of Health and Welfare.
Australia’s health 2010. The Twelfth Biennial Health
Report of the Australian Institute of Health and
Welfare. Canberra: Australian Government, 2010.
3. Franz MJ, VanWormer JJ, Crain AL, Boucher JL,
Histon T, Caplan W, et al. Weight-loss outcomes: a
systematic review and meta-analysis of weight-loss
clinical trials with a minimum 1-year follow-up. J Am
Diet Assoc 2007;107:1755–67.
4. Sacks FM, Bray GA, Carey VJ, et al. Comparison
of weight-loss diets with different compositions
Reprinted from AUSTRALIAN FAMILY PHYSICIAN VOL. 41, NO. 12, DECEMBER 2012
961
Evidence based exercise – clinical benefits of high intensity interval trainingclinical
patients: a randomized controlled study. Clin Rehabil
2012;26:33–44.
39. Little JP, Gillen JB, Percival ME, et al. Low-volume
high-intensity interval training reduces hyperglyce-
mia and increases muscle mitochondrial capacity
in patients with type 2 diabetes. J Appl Physiol
2011;111:1554–60.
40. Seals DR, Hagberg JM, Hurley BF, Ehsani AA,
Holloszy JO. Effects of endurance training on glucose
tolerance and plasma lipid levels in older men and
women. JAMA 1984;252:645–9.
41. Meyer P, Guiraud T, Gayda M, Juneau M, Bosquet L,
Nigam A. High-intensity aerobic interval training in a
patient with stable angina pectoris. Am J Phys Med
Rehabil 2010;89:83–6.
42. Munk PS, Breland UM, Aukrust P, Ueland T, Kvaloy
JT, Larsen AI. High intensity interval training reduces
systemic inflammation in post-PCI patients. Eur J
Cardiovasc Prev Rehabil 2011;18:850–7.
43. Moholdt TT, Amundsen BH, Rustad LA, et al. Aerobic
interval training versus continuous moderate exercise
after coronary artery bypass surgery: a randomized
study of cardiovascular effects and quality of life. Am
Heart J 2009;158:1031–7.
44. Trost SG, Owen N, Bauman AE, Sallis JF, Brown
W. Correlates of adults’ participation in physical
activity: review and update. Med Sci Sports Exerc
2002;34:1996–2001.
45. Thurston M, Green K. Adherence to exercise in
later life: how can exercise on prescription pro-
grammes be made more effective? Health Promot Int
2004;19:379–87.
46. King AC, Haskell WL, Young DR, Oka RK, Stefanick
ML. Long-term effects of varying intensities and
formats of physical activity on participation rates,
fitness, and lipoproteins in men and women aged 50
to 65 years. Circulation 1995;91:2596–604.
47. Bartlett JD, Close GL, MacLaren DP, Gregson W,
Drust B, Morton JP. High-intensity interval running is
perceived to be more enjoyable than moderate-inten-
sity continuous exercise: implications for exercise
adherence. J Sports Sci 2011;29:547–53.
48. Perri MG, Anton SD, Durning PE, et al. Adherence to
exercise prescriptions: effects of prescribing moder-
ate versus higher levels of intensity and frequency.
Health Psychol 2002;21:452–8.
49. Gibala MJ, Little JP, van Essen M, et al. Short-term
sprint interval versus traditional endurance training:
similar initial adaptations in human skeletal muscle
and exercise performance. J Physiol 2006;575(Pt
3):901–11.
50. Nielsen RO, Buist I, Sorensen H, Lind M, Rasmussen
S. Training errors and running related injuries: a sys-
tematic review. Int J Sports Phys Ther 2012;7:58–75.
51. Cornish AK, Broadbent S, Cheema BS. Interval
training for patients with coronary artery disease: a
systematic review. Eur J Appl Physiol 2011;111:579–
89.
52. Wise FM. Coronary heart disease: the benefits of
exercise. Aust Fam Physician 2010;39:129–33.
meta-analysis. BMC Public Health 2010;10:653.
22. National Vascular Disease Prevention Alliance.
Guidelines for the management of absolute car-
diovascular disease risk. 2012. Available at http://
strokefoundation.com.au/site/media/AbsoluteCVD_
GL_webready.pdf.
23. Woodcock J, Franco OH, Orsini N, Roberts I. Non-
vigorous physical activity and all-cause mortality:
systematic review and meta-analysis of cohort
studies. Int J Epidemiol 2011;40:121–38.
24. Boutcher SH, Dunn SL. Factors that may impede the
weight loss response to exercise-based interven-
tions. Obes Rev 2009;10:671–80.
25. Gibala MJ, McGee SL. Metabolic adaptations
to short-term high-intensity interval training: a
little pain for a lot of gain? Exerc Sport Sci Rev
2008;36:58–63.
26. Bar-Or O, Dotan R, Inbar O. A 30 seconds all out
ergometric test: its reliability and validity for
anaerobic capacity. Israel Journal of Medical Science
1977;113:226–30.
27. Boutcher SH. High-intensity intermittent exercise and
fat loss. J Obes 2011;2011:868305.
28. Perry CG, Heigenhauser GJ, Bonen A, Spriet LL. High-
intensity aerobic interval training increases fat and
carbohydrate metabolic capacities in human skeletal
muscle. Appl Physiol Nutr Metab 2008;33:1112–23.
29. Tjonna AE, Lee SJ, Rognmo O, et al. Aerobic interval
training versus continuous moderate exercise as a
treatment for the metabolic syndrome: a pilot study.
Circulation 2008;118:346–54.
30. Helgerud J, Hoydal K, Wang E, et al. Aerobic
high-intensity intervals improve VO2max more
than moderate training. Med Sci Sports Exerc
2007;39:665–71.
31. Trapp EG, Chisholm DJ, Freund J, Boutcher SH. The
effects of high-intensity intermittent exercise train-
ing on fat loss and fasting insulin levels of young
women. Int J Obes (Lond) 2008;32:684–91.
32. King J, Broeder C, Browder K, Panton L. A compari-
son of interval vs steady-state exercise on substrate
utilization in overweight women. Med Sci Sports
Exerc 2002;33:228.
33. O’Donovan G, Owen A, Bird SR, et al. Changes in
cardiorespiratory fitness and coronary heart disease
risk factors following 24 wk of moderate- or high-
intensity exercise of equal energy cost. J Appl
Physiol 2005;98:1619–25.
34. Lollgen H, Bockenhoff A, Knapp G. Physical activity
and all-cause mortality: an updated meta-analysis
with different intensity categories. Int J Sports Med
2009;30:213–24.
35. Molmen-Hansen HE, Stolen T, Tjonna AE, et al.
Aerobic interval training reduces blood pressure
and improves myocardial function in hypertensive
patients. Eur J Prev Cardiol 2012;19:151–60.
36. Guimaraes GV, Ciolac EG, Carvalho VO, D’Avila VM,
Bortolotto LA, Bocchi EA. Effects of continuous vs.
interval exercise training on blood pressure and arte-
rial stiffness in treated hypertension. Hypertens Res
2010;33:627–32.
37. Wisloff U, Stoylen A, Loennechen JP, et al. Superior
cardiovascular effect of aerobic interval train-
ing versus moderate continuous training in heart
failure patients: a randomized study. Circulation
2007;115:3086–94.
38. Moholdt T, Aamot IL, Granoien I, et al. Aerobic inter-
val training increases peak oxygen uptake more than
usual care exercise training in myocardial infarction
of fat, protein, and carbohydrates. N Engl J Med
2009;360:859–73.
5. Brunner EJ, Rees K, Ward K, Burke M, Thorogood
M. Dietary advice for reducing cardiovascular risk.
Cochrane Database Syst Rev 2007(4):CD002128.
6. Shai I, Schwarzfuchs D, Henkin Y, et al. Weight loss
with a low-carbohydrate, Mediterranean, or low-fat
diet. N Engl J Med. 2008;359:229–41.
7. Dauchet L, Amouyel P, Hercberg S, Dallongeville J.
Fruit and vegetable consumption and risk of coronary
heart disease: a meta-analysis of cohort studies. J
Nutr 2006;136:2588–93.
8. Wang C, Harris WS, Chung M, et al. n-3 Fatty acids
from fish or fish-oil supplements, but not alpha-lino-
lenic acid, benefit cardiovascular disease outcomes
in primary- and secondary-prevention studies: a
systematic review. Am J Clin Nutr 2006;84:5–17.
9. Dauchet L, Amouyel P, Dallongeville J. Fruit
and vegetable consumption and risk of stroke:
a meta-analysis of cohort studies. Neurology
2005;65:1193–7.
10. Sofi F, Cesari F, Abbate R, Gensini GF, Casini A.
Adherence to Mediterranean diet and health status:
meta-analysis. BMJ 2008;337:a1344.
11. Villareal DT, Chode S, Parimi N, et al. Weight loss,
exercise, or both and physical function in obese older
adults. N Engl J Med 2011;364:1218–29.
12. Egger G, Donovan R, Swinburn B, Giles-Corti B,
Bull F. Physical activity guidelines for Australians
– scientific background report. A report by the
University of Western Australia and The Centre for
Health Promotion and Research Sydney. In: Care.
Department of Health and Ageing, editor. Canberra,
1999.
13. Johnson NA, Sachinwalla T, Walton DW, et al.
Aerobic exercise training reduces hepatic and vis-
ceral lipids in obese individuals without weight loss.
Hepatology 2009;50:1105–12.
14. Fagard RH, Cornelissen VA. Effect of exercise on
blood pressure control in hypertensive patients. Eur J
Cardiovasc Prev Rehabil 2007;14:12–7.
15. Swardfager W, Herrmann N, Cornish S, et al.
Exercise intervention and inflammatory markers in
coronary artery disease: a meta-analysis. Am Heart J
2012;163:666–76 e1–3.
16. Lee CD, Folsom AR, Blair SN. Physical activity and
stroke risk: a meta-analysis. Stroke 2003;34:2475–
81.
17. Manson JE, Greenland P, LaCroix AZ, et al. Walking
compared with vigorous exercise for the prevention
of cardiovascular events in women. N Engl J Med
2002;347:716–25.
18. Tanasescu M, Leitzmann MF, Rimm EB, Willett WC,
Stampfer MJ, Hu FB. Exercise type and intensity in
relation to coronary heart disease in men. JAMA
2002;288:1994–2000.
19. Rossi A, Dikareva A, Bacon SL, Daskalopoulou
SS. The impact of physical activity on mortality in
patients with high blood pressure: a systematic
review. J Hypertens 2012;30:1277–88.
20. Davidson LE, Hudson R, Kilpatrick K, et al. Effects
of exercise modality on insulin resistance and
functional limitation in older adults: a randomized
controlled trial. Arch Intern Med 2009;169:122–31.
21. Cardona-Morrell M, Rychetnik L, Morrell SL, Espinel
PT, Bauman A. Reduction of diabetes risk in routine
clinical practice: are physical activity and nutrition
interventions feasible and are the outcomes from
reference trials replicable? A systematic review and
962
Reprinted from AUSTRALIAN FAMILY PHYSICIAN VOL. 41, NO. 12, DECEMBER 2012
... The most common model employed in low-volume HIT studies has been the repeated Wingate test, which consists of a 30 s 'all-out' cycling effort against a supra-maximal workload. Wingate-based HIT, which is known as sprint interval training (SIT), was typically performed for four to six work bouts separated by ∼4 min of recovery, for a total of 2-3 minutes of intense exercise during a training session that lasts ∼20 min with three sessions per week [5,9,10]. When compared on a matched-work basis or when estimated energy expenditure is equivalent, HIT can serve as an effective alternative to traditional endurance training, inducing similar or even superior changes in a range of physiological, performance and health-related markers in both healthy individuals and diseased population [5,9]. ...
... Wingate-based HIT, which is known as sprint interval training (SIT), was typically performed for four to six work bouts separated by ∼4 min of recovery, for a total of 2-3 minutes of intense exercise during a training session that lasts ∼20 min with three sessions per week [5,9,10]. When compared on a matched-work basis or when estimated energy expenditure is equivalent, HIT can serve as an effective alternative to traditional endurance training, inducing similar or even superior changes in a range of physiological, performance and health-related markers in both healthy individuals and diseased population [5,9]. ...
Article
Full-text available
Background: Different intensities of exercise induce varying levels of reactive oxygen species, causing oxidative stress. However, regular physical training enhances the antioxidant system and protects tissues by oxidative stress. This study aimed to investigate the difference in markers between time-efficient low-volume high intensity interval (sprint interval training: SIT) and traditional high-volume low-intensity methods (continuous endurance training: CET) regarding oxidative stress and antioxidant levels. Material and methods: Fifteen male volunteers were divided into two groups according to their VO2max levels. The SIT program consisted of 4–6 Wingate all-out sprints with a 4.5 min recovery, while CET consisted of 30–50 min cycling at 60% VO2max for seven weeks. Total oxidant status (TOS), total antioxidant status (TAS), plasma malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) levels were examined in pre and post-intervention. Results: Increases in GSH-Px (30% vs. 55%), TOS (33% vs. 18%) and a significant decrease in MDA (8.6%, p<0.003; 6.8%, p<0.016) in CET and SIT were observed, respectively. By contrast, TAS decreased (62%) after CET and increased (17%) after SIT. No significant differences in these parameters were reported after the training period between SIT and CET groups. Conclusions: SIT was suggested as a safe exercise model to improve general health and the performance of traditional CET.
... Genellikle YŞAA araştırmaları sporcularda, sedanterlerde ve çeşitli klinik popülasyonlarda atletik performansı iyileştirmek için etkili bir yöntem olarak ortaya çıkmıştır. 63,64 Ayrıca Dünya Sağlık Örgütü, yeni fiziksel aktivite tavsiyelerine daha yüksek yoğunlukta uygulanan aerobik egzersizleri dâhil etmiştir. 65 Ancak yakın tarihli bir araştırmada, Flockhart ve ark., yüksek yoğunlukta yapılan YŞAA uygulamalarının metabolik olarak zararlı etkileri olabileceğini öne sürmüşlerdir. ...
... Another study showed that PEMF produced an increase in blood flow velocity of the superficial small vein; In addition, it assumed that magnetic fields might reduce blood viscosity. And the increase in peripheral circulation may accelerate removal of metabolic wastes away from tissues and reduce pain [25] On the other hand, there was a significant improvement in NPRS, ABI and FMD% in group (B) that received HIIT. the improvement in this finding is in agreement withBarclay G., (2012)who reported that HIIT was shown to be superior to continuous, moderate aerobic exercise (CME) in improving endothelial function [26]. ...
... Over the years, HIIT has been shown to be an important training strategy to improve performance, both for competitive athletes and for non-athletes, and it is very effective in stimulating physiological adaptations, allowing for the improvement of different components of physical fitness [24][25][26]. Although the risk of musculoskeletal injury and cardiovascular events increases with higher intensity exercise, HIIT performed as a component of sports training has historically been associated with minimal risk [27]. Furthermore, this method has been extensively studied in different specific groups, showing ample safety, even in populations with different disorders [28] and during cardiac rehabilitation [29]. ...
Article
Full-text available
Introduction: Due to its highly dynamic characteristic and the time efficiency generated in relation to other training methods, High Intensity Interval Training (HIIT) has become a strategy used in different contexts. HIIT is understood as a training method that intersperses periods of effort performed at high intensity with periods of active (when an activity is performed at low intensity) or passive (when no activity is performed) recovery. Based on this concept that does not discriminate types of exercises, different HIIT models can be found in the literature, such as classic HIIT, Sprint Interval Training (SIT), HIIT with bodyweight, High Intensity Functional Training (HIFT), High Intensity Circuit Training (HICT), and High Intensity Resistance Training (HIRT), expanding the possibilities of applying HIIT to different purposes and audiences. Aim: a) to revisit, through a brief update, the concept of HIIT and its different aspects; b) present, from a scientific perspective, different protocols that can be applied based on the concept of HIIT and its effects. Conclusion: Based on the exposed concept and on the HIIT intensity control variables, this approach can be applied to different training modalities. In addition, it can be used as a strategy to provide safe and efficient training across different populations. RESUMO Introdução: Devido à sua característica altamente dinâmica e à eficiência do tempo gerado em relação a outros métodos de treinamento, o Treinamento Intervalo de Alta Intensidade (HIIT) tem se tornado uma estratégia utilizada em diferentes contextos. O HIIT é entendido como um método de treinamento que intercala períodos de esforço realizados em alta intensidade com períodos de recuperação ativa (quando uma atividade é realizada em baixa intensidade) ou passiva (quando nenhuma atividade é realizada). Partindo desse conceito que não discrimina tipos de exercícios, diferentes modelos de HIIT podem ser encontrados na literatura, como o HIIT clássico, Sprint Interval Training (SIT), HIIT com peso corporal, Treinamento Funcional de Alta Intensidade (HIFT), Treinamento em Circuito de Alta Intensidade (HICT), e Treinamento Resistido de Alta Intensidade (HIRT), ampliando as possibilidades de aplicação do HIIT para diferentes finalidades e públicos. Objetivo: a) revisitar, através de uma breve atualização, o conceito de HIIT e seus diferentes aspectos; b) apresentar, do ponto de vista científico, diferentes protocolos que podem ser aplicados com base no conceito de HIIT e seus efeitos. Conclusão: Com base no conceito expos-to e nas variáveis de controle de intensidade HIIT, esta abordagem pode ser aplicada a diferentes modali-dades de treinamento. Além disso, pode ser usado como uma estratégia para fornecer treinamento seguro e eficiente para diferentes populações. Palavras-chave: exercício físico; desempenho; saúde; aptidão física, treinamento intervalado de alta intensidade.
... Interval training, often referred to as high-intensity interval training (HIIT), is a training method where, in a single session, exercise bouts performed at high intensity are interspersed with periods of active or passive recovery, both lasting from a few seconds to a few minutes [1,2]. Many studies have shown that HIIT can be a time-efficient and enjoyable method to improve health, fitness, and sports performance for clinical populations, healthy subjects, and athletes [3][4][5]. Although HIIT is widely used in many sports [6], the prescription of HIIT sessions involves several parameters such as the number of sets and repetitions per set, the duration and intensity of the high-intensity and recovery intervals, etc. ...
Article
Full-text available
High-Intensity Interval Training (HIIT) is a time-efficient training method suggested to improve health and fitness for the clinical population, healthy subjects, and athletes. Many parameters can impact the difficulty of HIIT sessions. This study aims to highlight and explain, through logical deductions, some limitations of the Skiba and Coggan models, widely used to prescribe HIIT sessions in cycling. We simulated 6198 different HIIT training sessions leading to exhaustion, according to the Skiba and Coggan-Modified (modification of the Coggan model with the introduction of an exhaustion criterion) models, for three fictitious athlete profiles (Time-Trialist, All-Rounder, Sprinter). The simulation revealed impossible sessions (i.e., requiring athletes to surpass their maximal power output over the exercise interval duration), characterized by a few short exercise intervals, performed in the severe and extreme intensity domains, alternating with long recovery bouts. The fraction of impossible sessions depends on the athlete profile and ranges between 4.4 and 22.9% for the Skiba model and 0.6 and 3.2% for the Coggan-Modified model. For practitioners using these HIIT models, this study highlights the importance of understanding these models’ inherent limitations and mathematical assumptions to draw adequate conclusions from their use to prescribe HIIT sessions.
... Such high intensity training provides fitness and health improvements in less time per week than the recommended exercises guidelines (Heinrich, Patel, O'Neil, Heinrich, 2014). HIIT exercises significantly reduce subcutaneous fat, total body mass while improving VO2 max and insulin sensitivity (Shiraev, Barclay, 2012). This apart, many studies have examined the effects of HIIT in fat loss and health of special population such as overweight adolescents, older adults, diabetic individuals, paraplegics, intermittent claudication, chronic obstructive pulmonary disease and cardiac rehabilitation patients (Boutcher, 2011). ...
Article
Full-text available
Exercise has multiple health benefits and is a critical component in managing overweight and obesity. High Intensity Interval Training (HIIT) involves brief high-intensity anaerobic exercise followed by rest or very low intensity exercise. 24 men and women (age 18–60 years) volunteered to participate in a 6 weeks of modified HIIT exercises program where whole body functional training exercises was provided. Their body weight, body mass index, waist to hip ratio and skin fold fat were measured at the beginning and at the end of the 6 weeks duration . Statistical significance was found between the variables at p < 0.05. The results showed that a Modified HIIT exercise Program based on Body weight training results in considerable decrease in level of sub-cutaneous adiposity up to 77.8%. Obesity and overweight have become complex pandemic disorders where in physical inactivity and lack of time to exercise plays a major role leading to various complications. Reduction in adiposity through structured exercises protocols will improve body composition and Cardio-metabolic health . Novel interventions such as modified HIIT serve as the perfect pathway to address the time factor and enhancement of physical activity as well.
... Such high intensity training provides fitness and health improvements in less time per week than the recommended exercises guidelines (Heinrich, Patel, O'Neil, Heinrich, 2014). HIIT exercises significantly reduce subcutaneous fat, total body mass while improving VO2 max and insulin sensitivity (Shiraev, Barclay, 2012). This apart, many studies have examined the effects of HIIT in fat loss and health of special population such as overweight adolescents, older adults, diabetic individuals, paraplegics, intermittent claudication, chronic obstructive pulmonary disease and cardiac rehabilitation patients (Boutcher, 2011). ...
Article
Exercise has multiple health benefits and is a critical component in managing overweight and obesity. High Intensity Interval Training (HIIT) involves brief high-intensity anaerobic exercise followed by rest or very low intensity exercise. 24 men and women (age 18–60 years) volunteered to participate in a 6 weeks of modified HIIT exercises program where whole body functional training exercises was provided. Their body weight, body mass index, waist to hip ratio and skin fold fat were measured at the beginning and at the end of the 6 weeks duration . Statistical significance was found between the variables at p < 0.05. The results showed that a Modified HIIT exercise Program based on Body weight training results in considerable decrease in level of sub-cutaneous adiposity up to 77.8%. Obesity and overweight have become complex pandemic disorders where in physical inactivity and lack of time to exercise plays a major role leading to various complications. Reduction in adiposity through structured exercises protocols will improve body composition and Cardio-metabolic health . Novel interventions such as modified HIIT serve as the perfect pathway to address the time factor and enhancement of physical activity as well.
... Exercise or physical activity such as interval training or regular exercise, for example, moderate aerobic activity, running, walking, and swimming helps prevent and ameliorate several health problems including body mass index, blood lipids profile, hypertension, diabetes type 2, cancer, metabolic syndrome, heart attacks, stroke, depression, anxiety, and other mental illness [7][8][9][10][11][12][13]. It also has been found to improve social and sexual activities and moods, boost energy, and promote better sleep [14,15]. ...
Article
Full-text available
Bioenergetics is the study of energy flow between biological systems and the surroundings and is measured quantitatively. Energy flow can be affected by many variables, including lifestyle and exercise, where exercise comes in different types; endurance and resistance training play significant roles in enhancing bioenergetics and promoting health. In addition, a supplementary diet supports recovery and energy production. This review aims to study the effect of endurance training, resistance training, and supplement intake on the muscle cell's bioenergetics. As a conclusion of the information presented in this mini-review, it was found that resistance, endurance training, and supplements can increase mitochondrial biogenesis, fat oxidation, myofibril synthesis, and increase VO2 max.
... Ao longo dos anos, o HIIT tem se mostrado uma importante estratégia de treinamento para melhora do desempenho, tanto para atletas competitivos, como para não atletas, e é muito eficaz em estimular adaptações fisiológicas permitindo aprimoramento de diferentes componentes da aptidão física [24][25][26]. Embora o risco de lesão musculoesquelética e eventos cardiovasculares aumentem com exercícios de maior intensidade, o HIIT realizado como componente de treinamento esportivo tem sido historicamente associado a um risco mínimo [27]. Além disso, tal método tem sido amplamente estudado em diferentes grupos especiais, demonstrando ampla segurança mesmo em populações com diferentes desordens [28] e durante a reabilitação cardíaca [29]. ...
Article
Irisin, a novel exercise-induced myokine, has been shown to play important roles in increasing white adipose tissue browning, regulating energy metabolism and improving insulin resistance. Growing evidence suggests a direct role for irisin in preventing atherosclerosis (AS) by inhibiting oxidative stress, improving dyslipidemia, facilitating anti-inflammation, reducing cellular damage and recovering endothelial function. In addition, some studies have noted that serum irisin levels play an essential role in cardiovascular diseases (CVDs) risk prediction, highlighting that irisin has the potential to be a useful predictive marker and therapeutic target of AS, especially in monitoring therapeutic efficacy. This review summarizes the understanding of irisin-mediated regulation in essential biological pathways and functions in atherosclerosis and prompts further exploitation of the biological properties of irisin in the pathogenesis of atherosclerosis.
Article
Full-text available
Objective: To systematically review all the prospective cohort studies that have analysed the relation between adherence to a Mediterranean diet, mortality, and incidence of chronic diseases in a primary prevention setting. Design: Meta-analysis of prospective cohort studies. Data sources: English and non-English publications in PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials from 1966 to 30 June 2008. Studies reviewed Studies that analysed prospectively the association between adherence to a Mediterranean diet, mortality, and incidence of diseases; 12 studies, with a total of 1 574,299 subjects followed for a time ranging from three to 18 years were included. Results: The cumulative analysis among eight cohorts (514,816 subjects and 33,576 deaths) evaluating overall mortality in relation to adherence to a Mediterranean diet showed that a two point increase in the adherence score was significantly associated with a reduced risk of mortality (pooled relative risk 0.91, 95% confidence interval 0.89 to 0.94). Likewise, the analyses showed a beneficial role for greater adherence to a Mediterranean diet on cardiovascular mortality (pooled relative risk 0.91, 0.87 to 0.95), incidence of or mortality from cancer (0.94, 0.92 to 0.96), and incidence of Parkinson's disease and Alzheimer's disease (0.87, 0.80 to 0.96). Conclusions: Greater adherence to a Mediterranean diet is associated with a significant improvement in health status, as seen by a significant reduction in overall mortality (9%), mortality from cardiovascular diseases (9%), incidence of or mortality from cancer (6%), and incidence of Parkinson's disease and Alzheimer's disease (13%). These results seem to be clinically relevant for public health, in particular for encouraging a Mediterranean-like dietary pattern for primary prevention of major chronic diseases.
Article
Context Studies have shown an inverse relationship between exercise and risk of coronary heart disease (CHD), but data on type and intensity are sparse. Objective To assess the amount, type, and intensity of physical activity in relation to risk of CHD among men. Design, Setting, and Participants A cohort of 44452 US men enrolled in the Health Professionals' Follow-up Study, followed up at 2-year intervals from 1986 through January 31, 1998, to assess potential CHD risk factors, identify newly diagnosed cases of CHD, and assess levels of leisure-time physical activity. Main Outcome Measure Incident nonfatal myocardial infarction or fatal CHD occurring during the follow-up period. Results During 475755 person-years, we documented 1700 new cases of CHD. Total physical activity, running, weight training, and rowing were each inversely associated with risk of CHID. The RRs (95% confidence intervals [CIs]) corresponding to quintiles of metabolic equivalent tasks (METs) for total physical activity adjusted for age, smoking, and other cardiovascular risk factors were 1.0, 0.90 (0.78-1.04), 0.87 (0.75-1.00), 0.83 (0.71-0.96), and 0.70 (0.59-0.82) (P<.001 for trend). Men who ran for an hour or more per week had a 42% risk reduction (RR, 0.58; 95% CI, 0.44-0.77) compared with men who did not run (P<.001 for trend). Men who trained with weights for 30 minutes or more per week had a 23% risk reduction (RR, 0.77; 95% CI, 0.61-0.98) compared with men who did not train with weights (P=.03 for trend). Rowing for 1 hour or more per week was associated with an 18% risk reduction (RR, 0.82; 05% CI, 0.68-0.99). Average exercise intensity was associated with reduced CHD risk independent of the total volume of physical activity. The RRs (95% CIs) corresponding to moderate (4-6 MET's) and high (6-12 METs) activity intensities were 0.94 (0.83-1.04) and 0.83 (0.72-0.97) compared with low activity intensity (<4 ME Ts) (P=.02 for trend). A half-hour per day or more of brisk walking was associated with an 18% risk reduction (RR, 0.82; 95% CI, 0.67-1.00). Walking pace was associated with reduced CHD risk independent of the number of walking hours. Conclusions Total physical activity, running, weight training, and walking were each associated with reduced CHID risk. Average exercise intensity was associated with reduced risk independent of the number of MET-hours spent in physical activity.
Article
Physical activity has been shown to be beneficial for the prevention and management of hypertension. In the general population, physical activity has been shown to decrease mortality. The purpose of this systematic review was to identify and synthesize the literature examining the impact of physical activity on mortality in patients with high blood pressure (BP). An extensive search was conducted by two independent authors using Medline, Embase and Cochrane Library electronic databases (between 1985 and January 2012) and manual search from the reference list of relevant articles. Inclusion criteria were as follows: longitudinal design with minimum 1-year follow-up; hypertensive status of the cohort was indicated; and BP, physical activity, and mortality were measured. Six articles evaluating a combined total of 48 ,448 men and 47 ,625 women satisfied the inclusion criteria. Cardiovascular and/or all-cause mortality were shown to be inversely related to physical activity in all studies. For example, patients with high BP who participated in any level of physical activity had a reduced risk (by 16-67%) of cardiovascular mortality, whereas a greater than two-fold increase in risk of mortality was noted in nonactive individuals. However, activity classification and parameters, such as frequency, duration, intensity, and volume, as well as BP status, were not consistent across studies. Regular physical activity is beneficial for reducing mortality in patients with high BP. More research is needed to establish the impact of specific kinds of physical activity and whether any differences exist between sexes.
Article
The purpose of this systematic review was to examine the link between training characteristics (volume, duration, frequency, and intensity) and running related injuries. A systematic search was performed in PubMed, Web of Science, Embase, and SportDiscus. Studies were included if they examined novice, recreational, or elite runners between the ages of 18 and 65. Exposure variables were training characteristics defined as volume, distance or mileage, time or duration, frequency, intensity, speed or pace, or similar terms. The outcome of interest was Running Related Injuries (RRI) in general or specific RRI in the lower extremity or lower back. Methodological quality was evaluated using quality assessment tools of 11 to 16 items. After examining 4561 titles and abstracts, 63 articles were identified as potentially relevant. Finally, nine retrospective cohort studies, 13 prospective cohort studies, six case-control studies, and three randomized controlled trials were included. The mean quality score was 44.1%. Conflicting results were reported on the relationships between volume, duration, intensity, and frequency and RRI. It was not possible to identify which training errors were related to running related injuries. Still, well supported data on which training errors relate to or cause running related injuries is highly important for determining proper prevention strategies. If methodological limitations in measuring training variables can be resolved, more work can be conducted to define training and the interactions between different training variables, create several hypotheses, test the hypotheses in a large scale prospective study, and explore cause and effect relationships in randomized controlled trials. 2a.