High Intensity Interval Training is a method that combines brief periods of vigorous activity with brief rests. For example, 6-8 rounds of 20 second bursts on the stationary bike with 10 second rest periods in between rounds (yes, that’s the dreaded Tabata protocol).
Steady-State cardiovascular training involves working for lengthy periods of time at a moderate intensity, often at a target heart rate (percentage of maximum heart rate) or other quantitative method such as Rate of Perceived Exertion. An example of this would be a forty-five minute run at 65% of MHR.
HIIT vs moderate intensity cardio is quite a polarizing issue. For instance, it tends to sharply divide the “I hate jogging” crowd from the “I love jogging” crowd. In the interest of full disclosure, you’ll find me positioned squarely on the hate side of lengthy moderate intensity endurance training, despite my reputation for near limitless stamina. However, because I’m always such a diplomatic guy (cough), I’ll be doing my best to provide an objective analysis of each method in this article, as I see merit in both.
I’ll begin by stating that I believe specificity in training is necessary to maximize results. Conditioning training for a sport should reflect the anerobic and aerobic requirements of that particular sport. Many popular sports are largely games of intervals. Football and baseball involve very short periods of intense activity followed by periods of rest. Soccer has intense sprints interspersed with periods of lighter intensity running. Basketball has similar blend of requirements — jumping, quick lateral movements, some sprinting and a lot of lighter running in transition. On the flip-side of that are sports like cross-country skiing that require sustained continuous effort. Though an effective HIIT program provides an aerobic base that could theoretically carry you through a prolonged event of sustained physical exertion, I would still recommend that if you’re going to attempt, hypothetically, a marathon, that most of your training for it should consist of the style of running that the event will be comprised of. The reason for this is that a marathoner needs to teach him/herself how to respond to the many adverse effects of such an endeavor. For instance, if a runner never hits the proverbial “Wall” in training, then he/she will be unprepared to handle it properly in competition.
I should point out that it has been my personal experience that properly programmed HIIT can build an incredible base of endurance and do so very efficiently in condensed time periods (the studies I review below will reveal similar opinions). As always, remember that we are all individuals and should approach all challenges with that in mind. Precise training for a precise outcome.
However, the more pressing question for most people is that of which to employ when training for desired body composition — HIIT or traditional lengthy cardio training?
Also of great importance is the issue of overall health — are lengthy sessions needed, or is HIIT suited for the improvement and maintenance of proper cardiovascular function?
Without further ado, let’s go straight to the scientific studies. Roll up your sleeves, we’re about to get very academic.
High intensity interval training vs. high-volume running training during pre-season conditioning in high-level youth football.
Faude O, Schnittker R, Schulte-Zurhausen R, Müller F, Meyer T. A Saarland University, Institute of Sports and Preventive Medicine , Saarbrücken , Germany. J Sports Sci. 2013 Sep;31(13):1441-50. doi: 10.1080/02640414.2013.792953. Epub 2013 May 31.
“Both training programmes seem to be promising means to improve endurance capacity in high-level youth football players during pre-season conditioning.”
This study cuts right to the core of the issue: High intensity interval training versus high volume running training, using youth football players as test subjects (for you American folks, this study was done in Germany, where football = soccer). Unfortunately, the conclusion lacks any clear direction, except to say that both methods work. I suppose that’s a good starting point though. The take-away lesson from this study is that both methods are effective for general physical preparation for an endurance-based sport. If prolonged endurance training sessions make you happy, do it. If HIIT is more entertaining for you, it is a valid substitute for moderate intensity training.
Physiological and performance adaptations to high-intensity interval training.
Gibala MJ, Jones AM. Department of Kinesiology, McMaster University, Hamilton, ON, Canada.
Nutr Inst Workshop Ser. 2013;76:51-60. doi: 10.1159/000350256. Epub 2013 Jul 25.
“As little as six sessions of ‘all-out’ HIIT over 14 days, totaling ∼15 min of intense cycle exercise within total training time commitment of ∼2.5 h, is sufficient to enhance exercise capacity and improve skeletal muscle oxidative capacity.”
We’re still not really getting solid answers yet, although this article states in very concrete terms that HIIT is an effective at enhancing endurance performance without the time commitment of longer moderate intensity sessions. The study also provides specific parameters for the volume of HIIT that it takes to create desired adaptations for an aerobic base. Their recommendation translates to a 15-minute session performed 3 times per week. Nice, eh? HIIT isn’t easy, but it’s fast and effective.
High intensity interval exercise training in overweight young women.
Sijie T, Hainai Y, Fengying Y, Jianxiong W. Department of Health and Exercise Science, Tianjin University of Sport, China. J Sports Med Phys Fitness. 2012 Jun;52(3):255-62.
“The tangible results achieved by our relatively large groups of homogeneous subjects have demonstrated that the HIIT program is an effective measure for the treatment of young women who are overweight.”
Ah, now we’re getting somewhere. This study was conducted on overweight female college students and concluded that both the HIIT group and the sustained moderate intensity exercise group experienced benefits in body composition, cardiac function and aerobic capacity, but the HIIT group had slightly better results overall. Obviously, the effectiveness of both methods for body composition and cardiovascular health is of great importance, but particularly the HIIT method, which fits more easily into the average college student’s busy schedule of playing video games and watching Hulu (joking, sort of).
Impact of exercise intensity on body fatness and skeletal muscle metabolism.
Tremblay A, Simoneau JA, Bouchard C. Physical Activity Sciences Laboratory, Laval University, Ste-Foy, Quebec, Canada. Metabolism. 1994 Jul;43(7):814-8.
“Despite its lower energy cost, the HIIT program induced a more pronounced reduction in subcutaneous adiposity compared with the ET program. When corrected for the energy cost of training, the decrease in the sum of six subcutaneous skinfolds induced by the HIIT program was ninefold greater than by the ET program.”
I should mention that this is the first time I’ve ever seen the word “fatness” used in the title of a university study. In somewhat related news, fatness is my new favorite word. This study compared results of subjects who participated in a 15 week HIIT program to those who undertook a 20 week program of conventional endurance training. This is a victory for the HIIT camp, as the program resulted in greater subcutaneous fat loss even though the mean energy expenditure was less. These results further support the hypothesis that HIIT is an efficient training method for body composition goals.
Sex specific responses to self-paced, high-intensity interval training with variable recovery periods.
Laurent CM, Vervaecke LS, Kutz MR, Green JM. (1) School of Human Movement, Sport, and Leisure Studies, Bowling Green State University, Bowling Green, OH (2) Division of Applied Physiology, University of South Carolina, Columbia, SC (3) Department of Health, Physical Education, and Recreation, University of North Alabama, Florence, AL. J Strength Cond Res. 2013 Jul 8.
“These findings support the notion that women may demonstrate improved recovery during high-intensity exercise, as they will self-select intensities resulting in greater cardiovascular strain. Moreover, results confirm previous findings suggesting a 2:1 work-to-rest ratio is optimal during HIIT for both men and women.”
Oh good, males versus females. Hopefully the mere insinuation that males and females could have biological differences that impact physical performance enrages Billie Jean King enough to challenge some random elderly gentleman to a public athletic competition. But seriously folks, the most notable element of this study is that the abstract actually suggests an optimal work/rest ratio — 2:1. Aside from that, I’m pretty sure the author is saying that the male subjects were lazy.
Physiological responses to a 6-d taper in middle-distance runners: influence of training intensity and volume.
Mujika I, Goya A, Padilla S, Grijalba A, Gorostiaga E, Ibañez J. Departamento de Investigación y Desarrollo, Servicios Médicos, Athletic Club de Bilbao, Basque Country, Spain. Med Sci Sports Exerc. 2000 Feb;32(2):511-7.
“It is concluded that taper-induced physiological changes in trained middle-distance runners are mainly hematological, and that distinct physiological changes are elicited from LICT and HIIT during taper.”
This study is strictly focused on volume tapering after periods of intense training (think of this in terms of a periodization style program where the athlete would reduce training intensity and volume prior to competition). The researchers set a HIIT based taper against a low intensity continuous effort based taper in an effort to determine the physiological implications on intensity and volume. The findings concluded that effects on performance elicited by the different protocols were … drumroll please … insignificant. However, there were some physiological differences in blood profiles of the two groups that may be noteworthy to elite endurance athletes.
Effects of high vs. moderate exercise intensity during interval training on lipids and adiponectin levels in obese young females.
Racil G, Ben Ounis O, Hammouda O, Kallel A, Zouhal H, Chamari K, Amri M.Department of Biological Sciences, Faculty of Science of Tunis, University Tunis el Manar, Tunis, Tunisia. Eur J Appl Physiol. 2013 Jul 4.
“The results show that HIIT positively changes blood lipids and adiponectin variables in obese adolescent girls, resulting in improved insulin sensitivity, as attested by a lower HOMA-IR, and achieving better results compared to moderate-intensity exercise.”
Here’s another direct comparison of HIIT vs traditional cardio, this time in obese adolescent females. The researchers were specifically looking at lipid levels and adiponectin, which is a protein involved in regulation of glucose and breakdown of fatty acids. They declare HIIT the winner. Clearly, this study further supports HIIT as an effective method for achieving body composition goals. Have I made my point yet?
Long-term high-intensity interval training associated with lifestyle modifications improves QT dispersion parameters in metabolic syndrome patients.
Drigny J, Gremeaux V, Guiraud T, Gayda M, Juneau M, Nigam A. Montreal Heart Institute Cardiovascular and Prevention Center (ÉPIC) and “Université de Montréal”, 5055, St-Zotique Street East, Montreal, Quebec H1T 1N6, Canada. Ann Phys Rehabil Med. 2013 Jul;56(5):356-70. doi: 10.1016/j.rehab.2013.03.005. Epub 2013 Apr 17.
“In MetS, long-term HIIT and MICE training led to comparable effects on ventricular repolarization indices, and HIIT might be associated with greater improvements in certain cardiometabolic risk factors.”
Another study pitting HIIT against traditional cardio, this time for treatment of Metabolic Syndrome. For those unfamiliar with the term, Metabolic Syndrome is basically a fancy term for grouping together all the health problems that result from obesity. Obviously, this information should be of interest to, well… to phrase it politely, a whole lot of people. In this study they refer to steady state exercise as “Moderate Intensity Continuous Exercise” and abbreviate it as “MICE,” which I think most people will find adorable (hmm, does this indicate a steady state bias?). The result though, gives the advantage to HIIT. But the authors seem to suggest (as I do) that people who are overweight should please be doing something — anything — about it.
That’s a lot of information to digest in one day, especially if you’re like me and have the attention span of a gnat.
- For those who compete in a sport, the majority of your physical preparation should be focused on simulating the physical demands of the sport. If you play football, then squat, power clean, bench press and do interval sprints. If you run marathons, then run long distances at moderate intensities.
- In the case of off-season general physical preparation, HIIT is easily programmed into a periodized plan and can be used to build a base of aerobic conditioning.
- HIIT is an effective and efficient method to improve body composition.
- HIIT is an effective and efficient method to improve cardiovascular health.
- HIIT is an effective and efficient method to address health concerns related to obesity.
- HIIT is favorable for people with busy schedules.
- HIIT is fun for people with short attention spans.
- If you’re new to HIIT, a good starting point would be 15 minute sessions, 3 times per week, with a work/rest ratio of 2:1.
- Studies seem to indicate fairly equal benefits from varying methods, so if you prefer long moderate intensity sessions to shorter more intense workouts, then go with what you enjoy.
- Keep in mind that intensity and volume have an inverse relationship — as you increase one, it would be wise to decrease the other.
In the interest of general health, it’s most important to do something, regardless of which training style you utilize. Pick exercises you like and perform them on a consistent basis. Make adjustments as necessary, but stick with the program over the long-term. By long-term, I mean forever. Being physically active has a list of benefits a mile long. Whether you raise the intensity and lower the volume or the other way around, the most important thing is that you are improving your health and physical abilities. When I repeatedly make the point that increasing and/or maintaining cardiovascular health can be achieved in less than an hour of total workout time per week with HIIT, and likewise remind you that if you have physical limitations that stop you from engaging in intense exercise, you can still achieve health benefits in less than three hours of total workout time per week by working at lower intensities, that means that I’ve logically stripped away all possible excuses. So get moving.
Drigny J, Gremeaux V, Guiraud T, Gayda M, Juneau M, Nigam A. “Long-term high-intensity interval training associated with lifestyle modifications improves QT dispersion parameters in metabolic syndrome patients.” Montreal Heart Institute Cardiovascular and Prevention Center (ÉPIC) and “Université de Montréal”, 5055, St-Zotique Street East, Montreal, Quebec H1T 1N6, Canada. Ann Phys Rehabil Med. 2013 Jul;56(5):356-70. doi: 10.1016/j.rehab.2013.03.005. Epub 2013 Apr 17.
Faude O, Schnittker R, Schulte-Zurhausen R, Müller F, Meyer T. “High intensity interval training vs. high-volume running training during pre-season conditioning in high-level youth football: a cross-over trial.” A Saarland University, Institute of Sports and Preventive Medicine, Saarbrücken , Germany. J Sports Sci. 2013 Sep;31(13):1441-50. doi: 10.1080/02640414.2013.792953. Epub 2013 May 31.
Gibala MJ, Jones AM. “Physiological and performance adaptations to high-intensity interval training.” Department of Kinesiology, McMaster University, Hamilton, ON, Canada. Nutr Inst Workshop Ser. 2013;76:51-60. doi: 10.1159/000350256. Epub 2013 Jul 25.
Laurent CM, Vervaecke LS, Kutz MR, Green JM. “Sex specific responses to self-paced, high-intensity interval training with variable recovery periods.” (1) School of Human Movement, Sport, and Leisure Studies, Bowling Green State University, Bowling Green, OH (2) Division of Applied Physiology, University of South Carolina, Columbia, SC (3) Department of Health, Physical Education, and Recreation, University of North Alabama, Florence, AL. J Strength Cond Res. 2013 Jul 8.
Mujika I, Goya A, Padilla S, Grijalba A, Gorostiaga E, Ibañez J. “Physiological responses to a 6-d taper in middle-distance runners: influence of training intensity and volume.” Departamento de Investigación y Desarrollo, Servicios Médicos, Athletic Club de Bilbao, Basque Country, Spain. Med Sci Sports Exerc. 2000 Feb;32(2):511-7.
Racil G, Ben Ounis O, Hammouda O, Kallel A, Zouhal H, Chamari K, Amri M. “Effects of high vs. moderate exercise intensity during interval training on lipids and adiponectin levels in obese young females.” Department of Biological Sciences, Faculty of Science of Tunis, University Tunis el Manar, Tunis, Tunisia. Eur J Appl Physiol. 2013 Jul 4.
Sijie T, Hainai Y, Fengying Y, Jianxiong W. “High intensity interval exercise training in overweight young women.” Department of Health and Exercise Science, Tianjin University of Sport, China. J Sports Med Phys Fitness. 2012 Jun;52(3):255-62.
Tremblay A, Simoneau JA, Bouchard C. “Impact of exercise intensity on body fatness and skeletal muscle metabolism.” Physical Activity Sciences Laboratory, Laval University, Ste-Foy, Quebec, Canada. Metabolism. 1994 Jul;43(7):814-8.