What is HIIT?

Why HIIT Workouts May Be Right for You

It is well documented in the literature that exercise is important for the prevention of chronic (non-curable) illness.  HIIT workouts are a great way to maintain and improve cardiovascular and musculoskeletal fitness in a healthy population.

 However, what if you are already diagnosed with an illness? What type of exercise is safe and effective to improve strength, endurance, and overall stamina to reduce the risk of the illness getting worse? 

Several clinical trials have found that High Intensity Interval Training (HIIT) to be an effective and safe form of exercise in populations including those with limited exercise tolerance, diabetes, congestive heart failure, chronic obstructive pulmonary disease, intermittent claudication and sarcopenia.   Additionally, it has been found to be effective in women over the age of 65, as well as, long distance runners.^7-9,24  

Why participate in HIIT training?

Participation in HIIT for at least 7-12 weeks has been found to elicit the largest change in cardiorespiratory fitness as comparted to more traditional exercise.  Also, several studies have found high intensity interval training (HIIT) in patients with Cardiovascular disease (CVD) to be as safe as moderate intensity continuous training (MICT), yet more effective with regards to improving aerobic capacity, heart rate response, myocardial function, and quality of life.^8- There are no specific parameters in the research for those with CVD to follow, therefore working with a qualified Physical Therapist that can monitor blood pressure, heart rate, and form is important.^1-9

HIIT Defined

HIIT requires higher submaximal effort for a given task than other forms of exercise.  It is characterized by an individual performing exercise tasks with a Rating of Perceived Exertion (RPE) of 15-17 on the Borg scale.

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What is the RPE Scale?

BORG RPE SCALE

Rating

Percieved Exertion Level

6

7

Very, very light

8

9

Very light

10

11

Fairly light

12

13

Somewhat hard

14

15

Hard

16

17

Very hard

18

19

Very, very hard

20

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Does The Type of HIIT Routine Matter?

Numerous clinical trials have found that the type of HIIT task performed (i.e., cycling, calisthenics, rowing, running, or functional activities/functional training) does not significantly change cardiovascular fitness outcomes.^19-22 It is more important to participate in activities you enjoy in order for this type of training to be a long term solution to your health goals.

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Can I Still Participate in HIIT While Injured?

Even when recovering from an injury, you may still be able to safely training cardiovascular fitness by changing the load on the injured area to one that is tolerable.  For example, a runner with a foot injury might still be able to get on a rower, stationary bike, or swim.  This will help keep the participant’s cardiovascular fitness level high while still allowing the injury to heal, which results in improved personal satisfaction and faster return the preferred activity, which in this example is running.²³  It is important to note, working with a Physical Therapist to set a personalized plan of care for injury recovery and correctly dose the cross-training is important to avoid further injury and recover as quickly as possible.

What are the 3 Categories of HIIT Workouts?

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Duration Type

High Intensity Interval

(15-17 RPE)

Active Recovery

(12-14 RPE)

Number of Sets Performed

Proposed Timeline of Progression

Short 

(low exercise capacity)

15-60 sec

15-120 sec

10

0-3 weeks

Medium (intermediate exercise capacity)

1-2 min

1-4 min

8

4-12 weeks

Long 

(high exercise capacity)

3-4 min

3-4 min

4

>12 weeks

 Dun Y, Smith JR, Liu S, Olson TP. High-Intensity Interval Training in Cardiac Rehabilitation. Clin Geriatr Med. 2019, Nov;35(4):469-487. doi: 10.1016/j.cger.2019.07.011. Epub 2019 Jul 12. PMID: 31543179; PMCID: PMC6760312

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What Is an Active Recovery Period?

Complete lighter level activity that still keeps the heart rate (HR) elevated.  The Rating of Perceived Exertion (RPE) should range between 12-14 on the Borg scale.⁶

• Examples of active recovery exercises:some text
  • Walking
  • Jumping Jax
  • Jogging in place
  • Standing squats
  • Walking Lunges
  • Stationary bike
  • Rower

Are There Safety Concerns for Participating in HIIT?

If you are diagnosed with a chronic illness it is important that you be cleared from a physician to begin physical activity.  

• Key Ingredients to a Safe HIIT Workout:some text
  • Greater than 3-minute warm up
  • Greater than a 3 min cooldown that is carefully monitored. 
  • People taking antihypertensive medication- may have a sudden excessive reductions in blood pressure following exercise.   
  • People with known angina- a 10 minute warm up and cool down may be necessary.²⁵
  • During the first HIIT Workout- blood pressure should be monitored during the last 2 minutes of the first high intensity interval, to ensure normative changes to exercises demands.²³

Are There Contraindications to HIIT Workouts?

Quick Answer, Yes!

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Contraindications

Uncontrolled resting BP (>180 mmHg systolic and/or >110 mmHg diastolic)

<90% SPO₂ before or during exercise

Progressive worsening of exercise tolerance

Unstable HF

≥2 kg increase in weight previous 1-3 days

Signs and symptoms of hypovolemia

Exercising BP ≥220 mmHg systolic and/or≥105 mmHg diastolic BP

Resting supine HR >100 bpm

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Taylor JL, et al. Guidelines for the delivery and monitoring of high intensity interval training in clinical populations. Prog in Cardio Dis. 2019 Mar;62(2):140-146.

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To Sum It Up

The use of HIIT Workouts are a safe and effective way to progress and maintain fitness levels in a healthy population, as well as, with those diagnosed with chronic illness.  If you are diagnosed with chronic illness, it is important to be cleared by your physician for exercises and then work with a qualified Physical Therapist to assess vitals before, during and after training sessions, to ensure participation is safe and dosed properly.

 Exercise can be enjoyed by the vast majority of our population; it is important to support each other in order to help create the healthiest community as possible.

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REFERENCES

1. Piepoli MF, Hoes AW, Agewall S, et al. European Guidelines on cardiovascular disease prevention in clinical practice. Eur Heart J. 2016 Aug 1;37(29):2315-2381. doi: 10.1093/ eurheartj/ehw106. Epub 2016 May 23. PMID: 27222591; PMCID: PMC4986030.

2. Hannan AL, Hing W, Simas V, et al. High-intensity interval training versus moderate-intensity continuous training within cardiac rehabilitation: a systematic review and meta-analysis. Open Access J Sports Med 2018;9(1):1–17.

3. Rognmo Ø, Hetland E, Helgerud J, Hoff J, Slørdahl SA. High intensity aerobic interval exercise is superior to moderate intensity exercise for increasing aerobic capacity in patients with coronary artery disease. Eur J Cardiovasc Prev Rehabil. 2004 Jun;11(3):216-22. doi: 10.1097/01.hjr.0000131677.96762.0c. PMID: 15179103.

4. Warburton DE, McKenzie DC, Haykowsky MJ, Taylor A, Shoemaker P, Ignaszewski AP, Chan SY. Effectiveness of high- intensity interval training for the rehabilitation of patients with coronary artery disease. Am J Cardiol. 2005 May, 1;95(9):1080-4.

5. Kim C, Choi HE, Lim MH. Effect of High Interval Training in Acute Myocardial Infarction Patients with Drug-Eluting Stent. Am J Phys Med Rehabil 2015;94(10 Suppl 1):879–886.

6. 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(2):151–160.

7. Conraads VM, Pattyn N, De Maeyer C, et al. Aerobic interval training and continuous training equally improve aerobic exercise capacity in patients with coronary artery disease: the SAINTEX-CAD study. Int J Cardiol 2015;179(1):203–210.

8. Wisløff U, Støylen A, Loennechen JP, Bruvold M, Rognmo O, Haram PM, Tjønna AE, Helgerud J, Slørdahl SA, Lee SJ, Videm V, Bye A, Smith GL, Najjar SM, Ellingsen O, Skjærpe T. Superior Cardiovascular Effect of Aerobic Interval Training Versus Moderate Continuous Training in Heart Failure Patients. A Randomized Study. Circulation. 2007; 115:3086-3094.

9. Daussin F.N., Zoll J., Dufour S.P., Ponsot E., Lonsdorfer-Wolf E., Doutreleau S., Mettauer B., Piquard F., Geny B., Richard R. Effect of interval versus continuous training on cardiorespiratory and mitochondrial functions: Relationship to aerobic performance improvements in sedentary subjects. Am. J. Physiol. 2008;295:R264–R272. doi: 10.1152/ajpregu.00875.2007.

10. Hwang CL, Lim J, Yoo JK, Kim HK, Hwang MH, Handberg EM, Petersen JW, Holmer BJ, Leey Casella JA, Cusi K, Christou DD. Effect of all-extremity high-intensity interval training vs. moderate-intensity continuous training on aerobic fitness in middle-aged and older adults with type 2 diabetes: A randomized controlled trial. Exp Gerontol. 2019 Feb;116:46-53. doi: 10.1016/j.exger.2018.12.013. Epub 2018 Dec 18. PMID: 30576716; PMCID: PMC6404965.

11. Petersen MH, de Almeida ME, Wentorf EK, Jensen K, Ørtenblad N, Højlund K. High-intensity interval training combining rowing and cycling efficiently improves insulin sensitivity, body composition and VO2max in men with obesity and type 2 diabetes. Front Endocrinol (Lausanne). 2022 Nov 1;13:1032235. doi: 10.3389/fendo.2022.1032235. PMID: 36387850; PMCID: PMC9664080.

12. Buckley S, Knapp K, Lackie A, Lewry C, Horvey K, Benko C, Trinh J, Butcher S. Multimodal high-intensity interval training increases muscle function and metabolic performance in females. Appl Physiol Nutr Metab. 2015 Nov;40(11):1157-62. doi: 10.1139/apnm-2015-0238. Epub 2015 Jul 28. PMID: 26513008.

13. Menz V, Marterer N, Amin SB, Faulhaber M, Hansen AB, Lawley JS. Functional Vs. Running Low-Volume High-Intensity Interval Training: Effects on VO2max and Muscular Endurance. J Sports Sci Med. 2019 Aug 1;18(3):497-504. PMID: 31427872; PMCID: PMC6683610.

14. Bartlett JD, Close GL, MacLaren DP, Gregson W, Drust B, Morton JP. High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: implications for exercise adherence. J Sports Sci. 2011 Mar;29(6):547-53. doi: 10.1080/02640414.2010.545427. PMID: 21360405.

15. Rognmo Ø, Moholdt T, Bakken H, Hole T, Mølstad P, Myhr NE, Grimsmo J, Wisløff U. Cardiovascular risk of high- versus moderate-intensity aerobic exercise in coronary heart disease patients. Circulation. 2012 Sep 18;126(12):1436-40 doi: 10.1161/CIRCULATIONAHA.112.123117. Epub 2012 Aug 9. PMID: 22879367.

16. Giannuzzi P, Temporelli PL, Corra U, Tavazzi L; ELVD-CHF Study Group. Anti-remodeling effect of long-term exercise training in patients with stable chronic heart failure: results of the Exercise in Left Ventricular Dysfunction and Chronic Heart Failure (ELVD-CHF) Trial. Circulation. 2003; 108:554-559.

17. Sturdy G, Hillman D, Green D, Jenkins S, Cecins N, Eastwood P. Feasibility of High-Intensity, Interval-Based Respiratory Muscle Training in COPD. Chest. 2003; 123:142-150.

18. Hoff J, Tjønna AE, Steinshamn S, Høydal M, Richardson RS, Helgerud J. Maximal strength training of the legs in COPD: a therapy for mechanical inefficiency. Med Sci Sports Exerc. 2007; 39(2):220-6.

19. Adams J, Ogola G, Stafford P, Koutras P, Hartman J. High-intensity interval training for intermittent claudication in a vascular rehabilitation program. J Vasc Nurs. 2006 Jun; 24(2):46-9.

20. Gjellesvik TI, Becker F, Tjønna AE, Indredavik B, Lundgaard E, Solbakken H, Brurok B, Tørhaug T, Lydersen S, Askim T. Effects of High-Intensity Interval Training After Stroke (The HIIT Stroke Study) on Physical and Cognitive Function: A Multicenter Randomized Controlled Trial. Arch Phys Med Rehabil. 2021 Sep;102(9):1683-1691. doi: 10.1016/ j.apmr.2021.05.008. Epub 2021 Jun 6. PMID: 34102144.

21. Bonet JB, Magalhães J, Viscor G, Pagès T, Javierre C, Torrella JR. High-intensity interval versus moderate-intensity continuous half-marathon training programme for middle-aged women. Eur J Appl Physiol. 2020 May;120(5):1083-1096. doi: 10.1007/s00421-020-04347-z. Epub 2020 Mar 19. PMID: 32193662.

22. Liu QQ, Xie WQ, Luo YX, Li YD, Huang WH, Wu YX, Li YS. High Intensity Interval Training: A Potential Method for Treating Sarcopenia. Clin Interv Aging. 2022 May 26;17:857-872. doi: 10.2147/CIA.S366245. PMID: 35656091; PMCID: PMC9152764.

23. Cancela Carral JM, Ayán Pérez C. Effects of High-Intensity Combined Training on Women over 65. Gerontology. 2007 Jun 15; 53(6):102-108.

24. Van Gent RN, Siem D, van Middelkoop M, van Os AG, Bierma-Zeinstra SM, Koes BW. Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. Br J Sports Med. 2007 Aug;41(8):469-80; discussion 480. doi: 10.1136/bjsm.2006.033548. Epub 2007 May 1. PMID: 17473005; PMCID: PMC2465455.

25. Giannuzzi P, Temporelli PL, Corra U, Tavazzi L; ELVD-CHF Study Group. Anti-remodeling effect of long-term exercise training in patients with stable chronic heart failure: results of the Exercise in Left Ventricular Dysfunction and Chronic Heart Failure (ELVD-CHF) Trial. Circulation. 2003; 108:554-559.

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