What is HIIT? It’s an acronym for high-intensity interval training. Like the name suggests, HIIT is a type of interval training in which short periods of intense exercise are alternated with low-intensity recovery periods. HIIT workouts are gaining popularity, because both scientific evidence and anecdotal results demonstrate that short, intense workouts generate improvements to athletic capacity and conditioning, as well as improved metabolism in very little time. Typical HIIT workouts can be as short as five minutes, but on average they range between 20–60 minutes. In HIIT workout routines, high-intensity intervals of cardiovascular exercise, which may include running, cycling, and/or rowing (usually with the help of stationary machines), are performed at maximum or near maximum effort followed by recovery intervals of the same or different exercises done at about 50 percent effort. HIIT can also be done with weights, using compound movements such as squats and kettlebell swings, as well as bodyweight exercises like burpees and pull-ups. Some trainers like to combine cardiovascular exercise, weighted movements, and bodyweight exercises into HIIT routines.
Can Anyone do HIIT?
Some researchers hold the opinion that high-intensity workouts are not for everyone, and there are specific reasons that they typically cite. One line of reasoning holds that undertaking an HIIT workout routine, and seeing it through consistently, requires high levels of motivation—something that not everyone has. Others argue that HIIT is simply unsafe for the average person, and that it should only be undertaken by one who already exercises on a regular basis. But while it’s true that motivation and safety concerns should be factored into any workout plan, the American College of Sports Medicine1 notes that one of the main benefits of HIIT is adaptability, stating that “Unlike many more specialized workouts, it can easily be modified for all fitness levels, as well as special conditions including diabetes and overweight populations. And, HIIT programs can be built around many exercise modes…“ Intensity is a subjective term, after all. So long as form, muscle strength, and range of motion are considered in preparation for devising an HIIT workout plan, and there are no critical risk factors for heart disease, a history of dizziness, high blood pressure, or joint problems, then HIIT exercises should yield good results for anyone.
What Kind of Results are People Getting From HIIT?
People who work HIIT into their weekly workout schedule report that it delivers better health and fitness benefits than steady-state endurance training, and does so in a fraction of the time. ACSM reported at their 2011 Annual Meeting, that just two weeks of HIIT improves aerobic capacity as much as six to eight weeks of steady endurance-training. That same ACSM study mentioned earlier also reports that because of their vigorous nature, HIIT workouts help bodies burn more calories for hours after a workout has ended than other traditional exercise modes. In fact, a study at Colorado State University found just 150 seconds of intense exercise can burn as many as 200 calories over the course of the following 24 hours, thanks to the boosted resting metabolic rate created by an HIIT workout routine. The ACSM report continues, citing that HIIT workouts improve:
- Aerobic and anaerobic fitness
- Blood pressure
- Cardiovascular health
- Insulin sensitivity
- Cholesterol profiles
- Abdominal fat and body weight while maintaining muscle mass.
If the physical benefits aren’t enough, a study published by Montreal Heart Institute2 in 2012, found that after doing two HIIT workouts a week for four months, participants scored significantly higher on cognition tests and showed evidence of improved brain oxygenation.
Should Everyone Switch to HIIT?
So, this brings us back to the question of whether HIIT is right for everyone. The answer is a resounding yes…and no.
Yes, everyone who already has a regular workout routine should consider mixing HIIT into their routine. However, nobody should ‘switch’ to HIIT, per se. That is to say, nobody should trade in all their other modes of exercise to label themselves as strictly an HIIT athlete. There’s no such thing. The bottom line with high-intensity training is that ‘a little dab’ll do ya.’ Personal trainer Daniel Lagimodiere, cited in a 2014 article on MensHealth.co.uk3, points out that “One of the most common mistakes [with HIIT] is presuming more is better. Given the intense nature of interval training, you should do no more than three sessions of HIIT a week.” In fact, three times a week is high volume for HIIT. Many athletes and trainers consider twice-weekly HIIT workouts alongside your normal exercise modalities to be the real sweet spot. Most fitness trainers recommend at least 48 hours between HIIT workouts. Beyond that, and you’re trying to pour the ocean into a teacup—eventually, you’ll drown. Overtraining in any modality will tax your joints, your muscles, and your central nervous system. With HIIT, that stress comes on much faster. So, those who are interested in giving HIIT a try should begin by mapping out a plan.
Mapping Your HIIT Routine
According to ACSM, there are four factors to be considered when developing an HIIT workout plan. ACSM’s four factors are: 1. Duration, 2. frequency, 3. intensity of the workout intervals, and 4. the length of recovery intervals. We’ll get to those later because there are actually more factors to consider, namely fueling your HIIT workout through nutrition and supplementation. And once you begin to consider the question of nutrition and supplementation, you have to factor in specific goals related to performance and/or body composition, since those will inform your nutrition and supplementation choices moving forward.
Fueling Your HIIT Workout Based on Goals
What attracts people to putting any fitness regimen into practice are the effects. Weight loss, muscle size and strength increases, improvements to endurance and overall cardiovascular efficiency, and cutting body fat reported by researchers and athletes practicing HIIT, are all effects of HIIT. Each of those effects has a cause or set of causes that you don’t see concisely summarized very often. But, in 2012, two sports scientists at University of New Mexico6, Dr. Len Kravitz and Dr. Micah Zuhl, sum them up like this:
HIIT endurance effects — Caused by cardiovascular adaptations (VO2 max)
HIIT muscle building effects — Caused by teardown of muscle tissue, and rebuilding from protein and amino acids. HIIT followed by proper supplementation (such as with PROGENEX More Muscle, Recovery, and The Bar) aids in the rebuilding process.
HIIT fat burning effects — Caused by metabolic adaptations (increased mitochondria and fat oxidation)
HIIT weight loss effects — Caused by the above (combined with high protein/carb deficit diet)*
*Not listed by Kravitz and Zuhl
Most trainers will tell you the only meal more important than the one you eat right after a workout is the one you eat before it. HIIT workouts improve glucose tolerance and train your body to burn fat. That doesn’t mean you can follow an HIIT workout and still eat as much sugar as you want. Of course Before implementing your HIIT routine, you should consult a nutritionist and come up with a day-to-day diet plan.
HIIT Weight Loss — From burning more calories overall (compared to steady-state endurance training) to sparking as much as a 30 percent increase in fat oxidation (the breaking down of fatty tissue), to reduction in the fat-producing enzymes, there are a number of ways HIIT workouts help achieve a more trimmed-down overall silhouette, and a lower body weight. Depending on your day-to-day eating habits, you may not need to alter your macros or reduce your caloric intake at all. Practicing HIIT alone may put you into a slight caloric deficit all by itself, and you want to be careful not to lapse into a starvation diet. To maintain lean muscle mass and prevent any metabolic damage from starvation, you want to eat at least a gram of protein for every pound of bodyweight, and consume no less than 80 percent of the calories you burn. So, if your normal caloric intake is 2000 calories per day and you’re starting an HIIT routine, don’t even think about dipping below 1600 calories per day.
HIIT Increase Endurance — Kravitz and Zuhl noted that HIIT improves maximal aerobic capacity (VO2 max) for running, cycling, swimming, triathlons, and other endurance activities at superior rates to steady-state endurance training. Endurance athletes training at moderate duration and low intensity require about 2–3 grams of carbs per pound of body weight to fuel their workouts. Athletes training in large volume at high intensity require about 3–6 grams of carbs per pound of bodyweight.
HIIT Build Muscle and Strength — In 2013, German Sport University reported that high intensity interval sessions cause greater increases in free testosterone than steady state endurance4. How much more? Researchers in New Zealand measured testosterone increases of 100 percent in men practicing HIIT5. While steady-state endurance created a 60 percent increase in testosterone, a hormone closely associated with both muscle-growth and weight loss.
HIIT Cutting Body Fat — Cutting (i.e. getting ripped), means to visibly improved muscle tone and definition purely for the aesthetics, and is mostly reserved for competitive bodybuilders and fitness models. Done right, which is to say on a low-carb, high protein diet, cutting may not result in any measurable weight loss, just an impressive physique. But it isn’t something that can be maintained for long, and the process is anything but pleasant. Muscles need glycogen stores from carbs for functional energy. Without glycogen the body falls into a state of ketosis, meaning it starts burning body fat for it’s primary energy source. Ketosis comes with side effects like lethargy, fatigue, brain fog, and even depression. A typical ketosis diet begins with consuming .6 grams of carbs per pound of body fat—already a carb deficit—and reduces carb intake by .10 grams per week until you end up eating almost zero carbs, except on Sundays when you’ll do carbo loading. Again, high protein is key, as is high fat, because your muscles will be using fat for fuel. Carb cutting, when combined with proper supplementation and an intense HIIT regimen, can lead to a leaner, more defined physique.
HIIT Supplementation
With any type of rigorous workout, supplements are immensely beneficial. When thinking of which supplements to take, there are three critical time periods to consider: before, during, and after the workout. With pre-workout supplements, you’re looking for nutrients that prime your body for the workload you’re about to undertake. During the workout, you want something to keep your focus and motivation elevated all the way to the end. Finally, post-workout you want nutrients that will speed recovery so you can start looking forward to your next workout. Here are some tips for choosing the right supplements for your specific goals:
HIIT Weight Loss Supplements — Over the years, several supplements claiming weight-loss benefits have flooded the market. Chromium picolinate, conjugated linoleic acid (CLA), and green coffee extract, are a few of the more popular examples. None of their weight loss claims are backed by any conclusive scientific evidence, which is why Progenex doesn’t bother with fat-loss ingredients. The most effective supplementation relies instead on providing the body with the right nutrition, so that it can fuel its workouts and restore lost nutrients post-workout. As such, the increased lean mass and the metabolic adaptations that are triggered by HIIT are perfect for workout-focused supplementation.
HIIT Endurance Supplements — There are pre-workout supplements on the market that target the needs of endurance athletes with ingredients like creatine, beta-alanine, taurine, tyrosine. There are all pre-workout supplements that target body builders with muscle volumizing ingredients like arginine, citrulline malate, agmatine sulfate, and creatine monohydrate. Progenex Force strikes a carefully-calibrated balance of nutrients (Creatine and 2:1:1 BCAA Peptides), anti-fatigue ingredients—L-Citrulline and Beta-Alanine, with a low dose addition of caffeine. Progenex Force increases your energy, strength, stamina, clarity and mental focus, maximizing your ability to train harder, longer by fueling muscles and blocking fatigue pathways—perfect for HIIT training.
HIIT Body Fat-Cutting Supplement — As we have already discussed, cutting fat is about cutting carbs while increasing protein intake to preserve lean mass. The same supplements that help with recovery, stamina, and muscle building, will help with fat cutting as well. Beyond that, there isn’t anything that is both safe and effective that will cut fat exclusively. Because fat cutting requires a carb deficit, having a good protein supplement is the real secret weapon. Progenex Recovery contains the highest quality whey protein isolate available. The whey protein in Recovery is hydrolyzed through a proprietary enzymatic process that “cuts” the protein molecules into tiny peptide sequences that can be quickly absorbed into the bloodstream. How much better do athletes perform with PROGENEX Recovery? A 2014 study published in the International journal of sport nutrition and exercise metabolism demonstrated that athletes who consumed whey protein hydrolysate post-workout not only recovered faster, but also recovered stronger than those who did not7. PROGENEX “The Bar” also offers the same high-quality hydrolyzed whey protein, in the form of a convenient grab-and-go snack.
HIIT the Gym or the Road
Kravitz and Zuhl tell us that to be considered truly HIIT, workouts need to take you to at least 80 percent or more of maximum effort — enough to make carrying on a conversation difficult. Recovery intervals drop the effort to between 40–50 percent of maximum. Duration and frequency can vary based on the workout itself. For example, a 1:1 ratio workout would match four minutes of workout interval with a four minute recovery interval. Other workouts may involve 30 seconds of max intensity followed by four to four-and-a-half minutes of recovery—repeating this cycle three to five times. Their report gives several basic models for HIIT workouts that we’ll list below to help you get started with your own routine.
HIIT Track workout
Warm-up: Light 10 minute run around the track.
Interval: 800-meter runs at approximately 90 percent of maximal heart rate.
Each 800-meter interval should be timed.
Rest Interval: Light jog or walk for same amount of time it took to run each 800 meter
Work/Rest ratio: 1:1 The time for the interval (800 meters) and rest interval should be the same.
Frequency: Try to complete 4 repetitions of this sequence.
Cool Down: 10-min easy jog.
Pro Tips: The distance of the interval can be adjusted from 200 meters to 1000 meter. Also, the length of the rest interval can be adjusted.
HIIT Sprint Training
Warm-up: 10 minutes of light running.
Interval: 20-second sprints at maximal running speed.
Rest interval: 10 seconds of rest between each sprint. Light jogging or walking
Work/Rest ratio: 2:1 The work interval is 20-sec and rest interval is 10-sec.
Frequency: 3 groups or sets of 10–15 intervals. Take four minutes of rest between each set
Cool Down: 10 min easy jog
Pro Tips: The first few intervals should be slower allowing muscles to adapt to the workout. It is important to be safe and careful avoiding muscle damage during maximal sprinting exercise. The warm-up session is very important.
HIIT Treadmill Workout
Warm-up: 10 minutes of light jogging.
Interval: Set treadmill incline at five percent grade and speed at three mph. During each high intensity interval increase speed to between 5-6.5 mph, keeping grade at 5 percent. The length of the interval should be 1 min.
Rest Interval: Two minute rest interval with the walking speed set to 3 mph. Do not adjust incline.
Work/Rest Ratio: 1:2 ratio. The work interval is one minute and the rest interval is two minutes.
Frequency: 6–8 repetitions of this sequence
Cool Down: 5–10-minutes of easy jogging
Pro Tips: This is a hill running interval session. Incline, running speed, interval length, and rest interval can be adjusted during the interval session.
Sources:
- “The Basics Of High-Intensity Interval Training”. 2016. Certification.Acsm.Org. Accessed May 6 2016. http://certification.acsm.org/blog/2015/may/the-basics-of-high-intensity-interval-training.
- “Montreal Heart Institute”. 2016. Montreal Heart Institute. Accessed May 6 2016. https://www.icm-mhi.org/en/montreal-study-sport-makes-middle-aged-people-smarter.
- “What Is Hiit”. 2016. Menshealth.Co.Uk. Accessed May 6 2016. http://www.menshealth.co.uk/fitness/cardio-exercise/what-is-HIIT.
- “HIIT Vs. Continuous Endurance Training: Battle Of The Aerobic Titans”. 2016.Www.Ideafit.Com. Accessed May 7 2016. http://www.ideafit.com/fitness-library/hiit-vs-continuous-endurance-training-battle-of-the-aerobic-titans.
- “Science Behind HIIT.” Accessed July 7 2016. http://aibolita.com/fitness/32774-science-behind-hiit.html
- “HIIT Vs. Continuous Endurance Training: Battle Of The Aerobic Titans”. 2016.Www.Ideafit.Com. Accessed May 7 2016. http://www.ideafit.com/fitness-library/hiit-vs-continuous-endurance-training-battle-of-the-aerobic-titans.
- “Effect of Whey Protein Hydrolysate on Performance and Recovery of Top-Class Orienteering Runners.” 2014. Accessed July 7 2016. https://www.researchgate.net/publication/263971474_Effect_of_Whey_Protein_Hydrolysate_on_Performance_and_Recovery_of_Top-Class_Orienteering_Runners