High-Intensity Training: Why You Should Do It

High-intensity training

High-intensity training

High-intensity training (HIT), sometimes known as high-intensity interval training, is a form of exercise that takes only a few minutes a week, and has been shown to be vastly superior to traditional aerobic, or “cardio”, forms of exercise.


Aerobics as currently known is the brainchild of Dr. Kenneth Cooper, who postulated that exercise must be of a certain duration to be of cardiovascular and metabolic benefit. Running is perhaps the prime example of aerobics, and Dr. Cooper’s books led directly to the running craze of the 1970s, which continues to this day.

Running, however, has a number of drawbacks, including the possibility of heart damage, and when taken to an extreme leads to higher mortality risks. Not to mention the accumulated damage to knees and ankles from long periods of running.

As for other types of aerobics, such as using a treadmill at the gym, they are just all around less effective for health. They don’t build muscle, for one thing, have a pretty much terrible record in fat loss, and as we shall see here aren’t even all that metabolically effective.

High-intensity training

High-intensity training takes almost as many forms as there are practitioners, but in essence it involves very short periods of exercise of very high intensity, punctuated by short rest intervals. The short bursts of exercise normally last under a minute, even in some cases such as the Tabata workout, 20 seconds. The rest intervals can be, depending on the exercise, from 10 seconds to 4 minutes.

The following table gives the Tabata protocol in one study.

Exercises included in the 20-minute Tabata workout.

Minute 1 Minute 2 Minute 3 Minute 4
Segment 1 High Knee Run Plank Punch Jumping Jacks Side Skaters
Segment 2 Jump Rope In/Out Boat Line Jumps Push-Ups
Segment 3 Burpees Russian Twists Squats Lunges
Segment 4 Mt. Climbers Push-Ups Split Squat Box Jumps

Each exercise was repeated twice at a ratio of 20 sec exercise/10 sec rest

The original HIT workout was a strenuous one indeed, involving cyclists on a stationary bike peddling all out for from 30 seconds to 1 minute, with a rest interval of 4 minutes during which the cyclist peddled at a more relaxed pace. This could involve up to 10 iterations. Exercise like this leaves you winded and in a puddle of sweat.

Later, different forms of HIT were developed that people who were not trained athletes could do. For example, one form of the Tabata workout involves calisthenics, for example, burpees, jumping jacks, mountain climbers, or squat thrusts. Pushups, situps, jump rope, or any number of other exercises can be thrown in.

Sprints make a great HIT workout: running as fast as you can for 20 to 30 seconds, followed by walking up to 2 minutes; do this half a dozen times and you’ll know you’ve had a workout.

HIT can be done in the weight room too, using lighter weights and faster reps. For example, pullups for 30 seconds, rest, dips, rest, squats, rest, etc.

HIT is the best metabolic conditioning

So why is HIT so much better than aerobics? For one thing, it takes very little time; depending on the precise workout, you can get through one in 10 minutes, and even that might represent only 5 minutes of actual exercise. The biggest excuse people use for not exercising is lack of time, but with HIT that excuse is gone.

But more important than the time element is the improvement in metabolic and cardiovascular health. In one study, trainees exercising with HIT at four sessions a week of 8 x 20 second sets improved their cardiovascular fitness as much as those who ran on a treadmill for 30 minutes 4 times a week. Only the HIT trainees improved their muscle strength.

HIT is more effective for fat loss

HIT also seems to be much more effective for fat loss. While “effect of regular aerobic exercise on body fat is negligible”, HIT burns more abdominal and subcutaneous fat; the mechanisms here appear to be improved glucose tolerance and increased burning of fat by muscle.

HIT increases insulin sensitivity better than does steady-state aerobic exercise. Four, all-out bouts of sprinting of 30 seconds each increased insulin sensitivity by an amount more than 30% greater than did a session of continuous aerobic exercise.

Lifting is a form of HIT

Weightlifting as usually practiced is also a form of HIT. The caveat here is that rest intervals need to be kept relatively short, and the exercises themselves performed with intensity. Looking at your phone for 5 minutes between sets of curls unfortunately won’t cut it. The exercises should be one of the Big Five compound exercises (chest press, shoulder press, rows, squats and pull downs; throw in the deadlift for good measure) to ensure a good metabolic workout. These exercises work large parts of the body, not individual muscles so much, and performed with sufficient intensity will give you the insulin sensitivity of a teenager.


I believe that the evidence shows that high-intensity training is all around the best way to workout, whether you lift weights also or not. It takes far less time than aerobics and results in better metabolic and cardiovascular conditioning, and builds muscle too. So get off those treadmills, quit running for miles and miles, and do high-intensity training instead.


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  1. Joe E O says:

    I have started to monitor my blood glucose as to better dial in my protein and carb consumption level. I think that consuming 1 GM Protein/Lb of Body weight actually increases my insulin resistance so I am cutting back protein (and dairy).

    I have found the following
    1) Fasting really clears blood glucose – clearly this is the value of IF – spending time in in the fat burning zone i.e. light ketosis
    2) Aerobic exercise fasted really clears blood glucose even more. While fasting blood glucose levels are around mid 80s – 1/2 of riding the bike brings it down to low 70s. There is something else going on the because that bout of exercise just kills my appetite even though my blood sugar is quit low.
    3) Strength training fasted seems to raise my blood sugar (1 hour post workout). I have experienced this a couple times and I am trying to understand it. I assume that to some degree this is the “dawn effect” i.e. your fasting blood sugar increasing as the morning proceeds. Hopefully the cause is my liver producing glucose from stored fat in response to my workout.
    4) I am going to ride my aerobic exercise torture device (airdyne) early tomorrow I will try to add some sprints afterward to see what this does to my blood sugar.

    The issue I have with HIT is that I can’t do regularly and lift…it just burns me out as my strength training is pretty vigorous.
    The 1/2 hour of low impact aerobic work on the Airdyne actually helps me recover from lifting.


    Joe E O

    • P. D. Mangan says:

      Hey Joe, weightlifting does raise blood glucose, at least during the exercise itself. 1 hour post workout higher blood sugar I don’t know what to make of. I also agree with you that HIT is an intense addition to weightlifting; I have to be careful with it because it cuts into my lifting recovery time.

  2. John says:

    More vindication for HIT in a Denmark study, via the NYT last week:

    • P. D. Mangan says:

      Thanks, John. I myself find that HIT can be a bit too intense for me. I need enough recovery afterward that it cuts into my lifting routine. I may give this 10-20-30 routine a try.

  3. Erik Williams says:

    Great article Mangan and I really enjoyed Muscle Up as well.

    One thing I’m not clear on, what’s the optimal number of times per week to do a HIT workout when also doing weight training?

    Would you say HIT workout of 20 minutes twice a week as well as a weight workout like you describe in Muscle Up twice a week, or would you recommend a different cadence?

    Keep up the great articles, I learn more from this blog on health than any other source, everyone else seems to be playing catch up.

    • P. D. Mangan says:

      Erik, great questions. I hate to be so vague, but I think you need to listen to your body. Fatigue is a sign you’re doing too much. If no fatigue, then the twice a week HIT and twice a week weights sounds like plenty. Myself, I find I’m doing little HIT cardio lately because it cuts so much into my recovery from my lifting, which is my main focus.

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