What it is
High-Intensity Interval Training (HIIT) is translatable as “high-intensity interval training”. Less commonly “high-intensity intermittent exercise” (HIIE) or sprint interval training (SIT). A method of training based on the conjugation of two basic principles: High-Intensity Training and Interval Training.
Principles of High-Intensity Interval Training (HIIT)
- HIT: High-Intensity Training: High-intensity training, from which came the design of “Heavy Duty” by bodybuilder Mike Mentzer. More generally, it defines any activity requiring a massive undertaking of anaerobic metabolisms.
- EN Interval Training – interlace training: common examples of IT are the repeated aerobic sports. And certain circuit training for muscle enhancement.
- The High-Intensity Interval Training is the alternation of short, intense efforts, therefore with a large anaerobic component. Following by periods of underdevelopment – usually active – until reaching muscle and/or metabolic exhaustion.
The duration and intensity of the peaks are inversely proportional since the effort should be ceiling or sub-ceiling. Although there is no precise and recommended overall duration. HIIT workouts typically last less than 30 minutes, with times varying depending on your level of training.
How do you do it?
HIIT training sessions generally consist of:
- General and specific heating, possible activation/approach
- A series of repetitions or repeat series of high-intensity exercises (HIT). Separated by low or medium-intensity executions such as active recovery
- Fatigue and any exercises for flexibility and mobility.
It is important to perform HIIT at maximum intensity, without exceeding the active recovery of 50%. The number of sets/rep and the duration of each operation depends on the type of operation. But can be just 3 rep per 20”. The specific exercises performed during the high-intensity moments may also vary within the same training. Most of the HIIT research was carried out using an exercise bike. But can replace effectively with:
- treadmill
- stepper
- remote meter
- excite
- climb mill, etc.
There is no specific HIIT formula. Depending on your cardiovascular and muscle level, the recovery intensity can be medium or very slow; what matters is high-intensity peaks. A common formula includes:
- a ratio of high intensity to the active recovery of 2:1
- 30-40” fast running alternating 15-20” jogging or walking
- repeated “X” times or until exhaustion.
The entire HIIT session can last from 4 to 30 minutes. This means an excellent way to maximize training in case of time limits. A watch or a timer is strongly recommended. To meet exercise, recovery time, and to estimate beats per minute (bpm) – or a heart rate is extremely useful.
Voltage VS Volume
Intensity and volume are two parameters that, along with density, constitute the workload (intensity + volume + density = TOT load).
The HIIT is based, as mentioned above, on HIT (high-intensity training). Associates with IT (interval training) to increase total volume.
How long would I be able to achieve 90-95% of the maximum pulsations? For example, 10. How many times would I be able to repeat identical progressions, but lasting up to 1’00” with 30” active recoveries? Even 15, for a total of 15′ at the same intensity. Note: the example is purely indicative and has no reference to actual athletic capabilities.
It must be said. However, that “high intensity” is a relative concept. In the sense that it can be applied to efforts of a different nature. And that they use equally different metabolisms. It is common to use to speak of high volume training and low intensity (Low Intensity). For all low-strenuous aerobic resistance activities:
- light stroke of one hour
- equally sober cycling for 2-3 hours
- sustained walking for 90”, etc.
In this case, the intensity is objectively low; what happens, however, if we bring the same concept back to protocols that stimulate the metabolism of anaerobic intensity?
In enhancement workouts, the speech doesn’t fundamentally change. yet the metabolisms recruited are mainly anaerobic, skull, and lactation.
Why do we do that?
To distinguish the various coaching strategies, which have different aims.
When we think about the training of a bodybuilder, knowing that the muscle mass is searching in different directions, we could see different phases with different characteristics:
- Development of concentric “pure” force: for example, with a short and quick table, multifrequency in the microcycle, based on a few exercises of 5 set x 5 rep to 90% of 1RM, low TUT, in which the recovery is almost total
- Research for hypertrophy due to depletion of energy supplies, high lactic acid production, emphasis on isometry, and the eccentric phases of contraction: with long sessions of 10-12 rep to 75% of the 1RM x 4 sets, with shorter recoveries, high TUT, many more exercises, almost always in single frequency in the microcycle.
The latter method, which prolongs training to 75-90 inches, versus the 30-40 inches of the previous one, in the context of muscle strengthening training, can be considered a high volume and less intensity system – although it has nothing to do with the long walks we have talked about above.
What’s It For?
The HIIT is designed to increase exercise efficiency, both in terms of physical conditioning (muscular and metabolic) and in terms of energy consumption infra and post-exercise – Excess Postexercise Oxygen Consumption (EPOC) or “afterburn” or oxygen debt after exercise.
HIIT training can achieve better physical health and higher athletic capacity; In this case, the High-Intensity Interval Training determines an improvement in glucose (glucose and insulin sensitivity) metabolism.
HIIT vs Low-Intensity High Volume Training (LIHVT)
Compared to aerobic low-intensity high volume training (LIHVT), HIIT may not be as effective at:
- Treatment of hyperlipemias, in which low intensity and prolonged training seems to work more by reducing triglyceridemia and improving cholesterolemia
- Treating severe obesity and uncomfortable conditions or conditions, such as severe heart disease, bronchopathies (e.g. COPD), etc.
- Muscle and restoration of bone mass in people with sarcopenia, osteopenia, and osteoporosis.
However, research has shown that HIIT regimens can induce – on equal caloric intake compared to LIHVT – significant reductions in body fat mass.
Other insights, however, have highlighted that the HIIT requires “an extremely high level of personal motivation” by asking whether the general population can safely or practically tolerate the extreme nature of the method – especially in the context of motor therapy.
Benefits
Let’s now list the health effects of High-Intensity Interval Training.
Heart Health Benefits of HIIT
A systematic review in 2015 and meta-analysis of randomized studies found that HIIT training and LIHVT training both lead to a significant improvement in cardiovascular disease in healthy adults 18 to 45 years of age, but greater improvements in VO2 max were seen in those participating in the HIIT exercise regimen.
Another analysis also found that 30-day or more HIIT regimens effectively improve cardiovascular fitness in adolescents and lead to moderate improvements in body composition.
Also, a separate systematic review and meta-analysis of seven small randomized studies have found that HIIT (defined as four-minute intervals at 85-95% of maximum heart rate at three-minute intervals at 60-70% of FcMax) was more effective than continuous moderate-intensity training to improve blood vessel function and blood vessel health markers.
HIIT and cardiovascular disease
A 2015 metanalysis comparing HIIT with moderate-intensity continuous training (MICT) in subjects with coronary artery disease found that the HIIT leads to higher VO2 increases max but that MICT leads to higher body weight and heart rate reductions.
A 2014 meta-analysis found that the cardiorespiratory fitness, as measured by VO2 max, of subjects with lifestyle-induced chronic cardiovascular or metabolic diseases (including hypertension, obesity, heart failure, coronary artery disease, or metabolic syndrome) that completed a HIIT exercise program, was almost twice that of individuals completing an MIT exercise program. ICT.
Metabolic Benefits of HIIT
HIIT significantly reduces insulin resistance to low-intensity training or inactivity conditions and leads to a modest reduction in fasting blood glucose levels as well as an increase in weight loss compared to those who do not suffer from physical activity.
Another study found that HIIT was more effective than continuous moderate-intensity training in reducing fasting insulin levels (31% decrease and 9% decrease).
HIIT and Fat Oxidation
A 2007 study looked at the physiological effects of HIIT on the oxidation of fats in moderately active women.
The study participants performed HIIT (defined as ten sets of 4-inch cycle repeat with a 90% VO2max intensity spaced from 2′ rest) every other day for 2 weeks. The study found that 7 HIIT sessions over 2 weeks improved body fat oxidation and the skeletal muscle’s ability to oxidize fat in moderately active women. A 2010 systematic review of HIIT summarized the HIIT findings on fat loss and stated that HIIT may result in modest reductions in subcutaneous fat in young, healthy subjects but greater reductions for overweight individuals.
Health and mastermind efficiency
A 2017 study looked at the effect of HIIT on cognitive performance in a group of 318 children. The authors show that HIIT is beneficial for cognitive control and working memory capacity compared to “a mix of table games, computer games, and quizzes” and that this effect is mediated by the neurotrophic factor derived from the brain (BDNF). They concluded that the study “suggests a promising alternative to better cognition, through short and powerful exercise regimes.”
Application
Since the concept of “high” intensity is related to a specific athletic capacity, HIIT can be contextualized in different areas: short, medium, and long-term exercises/sports.
Short-term HIIT with an anaerobic latex and lactic base
If referring to short-term exercises with an anaerobic base in the high-rise and milky-acid area, the HIIT covers either the maximum or sub-ceiling expression of force/rapid/explosive, which are of resistance to force/speed/explosiveness, both as close as possible to its limit. The limiting factor is always lactic acid. For example, in the first case, 3 flat bench repetitions (rep) to 90% of the 1RM, spaced by a recovery of 6-7′, could be performed for a number that was set to achieve the inability to continue with work. In the second case, however, 25 burpees could be performed in 1’00’, with a recovery of 20”, for a number that could reach the inability to continue with work.
Medium and long-term HIIT with anaerobic basis completed by anaerobic lactic metabolism
When referring to medium- and long-term exercises with an aerobic base completed by the anaerobic lactic metabolism, it primarily concerns the expression of speed resistance – rapid but cyclical movement, such as travel, cycling, swimming, rowing, etc – or resistance to the medium and long-term strength – capacity used in particular sports, such as judo and Brazilian jujitsu, in which, for example, the fight to land requires to maintain isometric contractions even for several minutes.
For example, in the first case – as in the race – you could make 5 fluctuations in rhythm progressing from 3′ up to 90% of the maximum pulsations, alternating them with 1’30’ of passive recovery, which should ensure a drop of beats up to 135-145 per minute (bpm). In the second, a circuit training with various isometric positions (isometric squat, plank, side plank, dip trust, etc.) could be established, lasting 3’00’ each, spaced by 1’30” aerobic exercise, such as rope jump, stroke, cyclists, etc.
Types
Peter Coe
It’s a kind of HIIT with short recovery periods that was used in the 1970s by coach Peter Coe. Inspired by the principles of Woldemar Gerschler and the Swedish physiologist Per-Olof Åstrand, this included sessions that included 200-meter quick race tests with only 30”’ recoveries.
Tabata
It is a HIIT version based on a 1996 study by Professor Izumi Tabata from the University of Ritsumeikan et al. It is based on 20-inch ultra-intense exercise (approximately 70% VO2max) followed by 10-inch rest, repeated continuously for 4 minutes (8 cycles).
Gibala
A 2010 study by Professor Martin Gibala and his team at McMaster University in Canada is based on this structured HIIT: 3′ heating, 60” of 8-12 cycles of VO2max, 75” rest. The benefits are similar to those expected from a 50-70% VO2max constant five times a week.
Zuniga System
Jorge Zuniga, assistant professor of motor sciences at Creighton University, proposes a 30′ to 90% HIIT2 max, followed by 30” rest. Alternative protocols included 100% of the maximum output or 90% for 3′.
Vollaard
Dr. Niels Vollaard of the University of Stirling offers a 10-inch training routine that consists of 6-10 sprint ceilings of 30′.