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The Best Way to do High Intensity Interval Training

By Kim Crawford, M.D. Last updated: September 6, 2018
best way to do high intensity interval training

Why all the fuss about high intensity interval training?

Have you heard of HIIT? Better yet, have you experienced a HIIT workout? Did you know researchers have been seeking the best way to do high intensity interval training for nearly a decade? The goal and the findings have been more than expected.

I’m assuming that if you found this article you have heard of HIIT and know it’s good for you. Perhaps you have been told one way to do it, then read another way, and wonder what is the best way to do high intensity interval training for longevity, fat loss, weight control, energy, and disease prevention (all studied!)

I’ve digested all the research and below I’m going to dissect that information for you. I’ll also reveal what I’m currently recommending to my patients, AWS members and friends who are looking to shed a few pounds, increase their lifespan and have more energy to perform at peak all day.

Introduction to HIIT Research

At first, researchers appeared to be seeking to minimize the time spent for the exerciser, to simply get more people exercising. Then, the research emerged about how high intensity interval training (HIIT) was superior to “regular workouts” for fat loss. Then came more and more studies looking at things such as control of glucose, blood pressure, cholesterol, triglycerides and maintenance of weight.

There are even studies which compare skin thickness (translation: collagen production) in regular versus HIIT exercisers. Right now, mitochondrial function and health is one of the hottest topics in anti-aging medicine. The little energy factories, called mitochondria, which produce ATP (cellular energy) are crucial for what is now called “optimal aging” as well as disease prevention.

HIIT for Mitochondrial Health:

High intensity vs. regular exercise training has been compared many times in many different studies. HIIT “wins” each and every time. That doesn’t mean you shouldn’t walk your dog, or go to the gym. Those are still healthy things to do. Those will also help your mitochondrial (and therefore total) health. However, you should add HIIT to your regimen. To review, mitochondria die off as you age and/or contract diseases. In addition, with advancing age and disease comes less new mitochondria and less ATP production (mitochondrial biogenesis).

HIIT for VO2 Max:

Cardiovascular (aerobic) fitness is basically the amount of oxygen your mitochondria are able to consume when you push yourself to the limit. The measurement is called your VO2 max. We used to routinely measure this on all fitness club members in the gyms I used to own. It’s easy to do—just ask at your local gym. Why do you want to know what your number is? Studies have shown that the lower your VO2 max, the higher your risk of chronic diseases such as cancer, heart disease, diabetes, auto-immune illness, Alzheimer’s disease and so on. On the flip side, the higher your VO2 max, the more positive markers of health and longevity you will have.

Olympic cross-country skiers tend to have the highest VO2 max levels topping the charts at 78 milliliters per kilo (2.2 pounds per kilo) per minute. The average “score” for a VO2 max differs for exercisers and nonexercisers. Here is a chart you can check to see where you stand.

The conventional recommendation from the American College of Cardiology is to get 150 minutes of moderate exercise each week. That works out to a 30-minute slow jog or brisk dog walk 5 days per week.  On top of that, it is recommended you also squeeze in at least two weight training sessions. The problem is that most people are fighting for enough time to sleep. Plain and simple—In survey after survey, people know they need to exercise but say they just don’t have the time. HIIT solves that problem. VO2 max gains for the type of workout I’m going to describe are the same as doing the infamous 150 minutes per week.

HIIT for your looks:

We have known “forever” that how your skin looks is a function of inside-out care. However, now we know that HIIT is even better than “regular exercise” to stimulate collagen production.  Therefore, it may be the best form of anti aging skin care there is! Studies are ongoing to see if cold therapy (cryotherapy) will de-age the skin. I’m mentioning this because one of the exercises I’m going to name seems to me to have built-in skin benefit’s—Swimming! Now let’s get down to HIIT!  Please remember: if you are a couch potato, over 40 and/or have cardiac risk factors you need “medical clearance” to start any exercise program.

HIIT Basics:

Basic HIIT is actually easy and fun. There have been numerous studies over the past 2-3 years as HIIT receives more attention due to its multifactorial benefits. We have learned that you can increase your heart and lung capacity (VO2 max) as well as your mitochondrial function just as easily with HIIT  as you can with doing a daily (5x/week) 30-minute jog. To point out, the other benefits discussed above are lining up to be in accordance with this information as well.

How to “do HIIT”: 

You need to conceptualize how HIIT is going to feel. This is not going to feel like a quick walk to the mailbox, but neither will it “knock you out” as you might be expecting. When you do HIIT, you are “going full out”—past what is known as your anaerobic threshold, which is technically more than 85% of your VO2 max. When you are “going full out,” you are going as hard and fast as you can to become “breathless.” The secret to my HIIT is that you will be breathless, but you will not be gasping for air. Studies have examined intervals of “going full-out” from 30 seconds to as much as 4 minutes.

Rest periods in-between “full-outs” logically then vary from 1 minute to 3 minutes. The number of times per week vary from twice weekly (for the 4 minute intervals) to five times per week for the 30 second intervals. The studies prove what we all can find to be logical. The more time you spend doing HIIT, the fewer times per week it appears that you need to do it. My description/recommendation of how to do it is an amalgam of the studies I’ve mentioned, based on what my patients, AWS members and I find easiest to do. If weight and fat loss is a goal, add some natural metabolic boosters.

If you have access to a swimming pool, track, or cycling course, your HIIT sessions will be more fun. The HIIT lasts 30 seconds (more or less) and the rest period between HIIT’s is about 1 minute. When you do this “my way” you are approximating the time after a few practice runs. You will need to figure out how it feels to go above your anaerobic threshold. Hint: You will be short of breath and feel your heart beating rapidly. You can even do this scientifically, figuring out your maximal heart rate, calculating 85-90% of your “max” and taking your pulse to check.

However, most of us can just “feel” it. So, for the first couple of times, get some help to time yourself. You’ll quickly learn what it feels like to go full-out and to then recover (catch your breath) enough to go full-out again. If you are at all fitness-trained, simply follow the instructions below.  If you are untrained, you might last only 15-20 seconds at first, and need up to 2 1/2 minutes to “catch your breath.”

Details on the best way to do high intensity interval training :

best way to do high intensity interval trainingOn a track:

Run what will be approximately a 200-meter dash or 1/2 a lap. Then very slowly, just walk around the track for another minute or about 1/4 of a lap.

Recall, at first, it helps to have a buddy tell you when the 30 sec and 1-minute “marks” are.

However, if you are doing it on your own, these are the approximate distances.

DO Make sure you have caught your breath before running full-out again.

Do this 2-3 times if you’re untrained. When fully trained, do this 6 times, 5x per week. If you are a cyclist and have access to a course, you will need to have someone time this out for you, or use a timer on your bike for the 30-second intervals and approximate the recovery time.

In a pool:

Dive in to get the mitochondrial “cold boost,” then swim full out what is usually 3 laps in a 50-meter pool. Stand up or float on your back until you are breathing normally to then get swimming again. The time intervals are the same as above. As they say: rinse and repeat. The goal is 6x HIIT intervals, 5 times per week.

In the gym:

Set the timer on your phone, ask a friend or hire a trainer to time you on HIIT’s and rest intervals. Use a bike, treadmill, or flywheel rower. You’ll do exactly the same method as above, but you won’t be able to approximate your distance. You’ll need some sort of timer or buddy or trainer to get in your HIIT’s.

What about weight training?

Indeed this has been studied, but it has been “mixed up” with cardio, and there is no “full body” routine available. It seems logical that weight training for 30 seconds “full out” with a minute rest in-between a full out set would accomplish the same metabolic goals. While we wait for the studies, here is how I would suggest you approach your weight training. For two of your five HIIT days, my “shortcut to a great body” workout would be how you would structure YOUR weight workout using the HIIT guidelines. If you have questions about this, just email me.

For those of you hardcore weightlifters, I know that doing cardio while weight training may diminish strength and mass gains. However, doing the quasi-super-slow method in the article just referenced results in very similar strength and muscle gains. If muscle mass is a question for you and you’d like to experiment, you might want to add some weight lifting supplements such as ALC and BCAA’s.


I am asking you to make this part of your daily routine. You’ll find, as many of my patients and I have, that HIIT is a glorious way to wake up or have a work-break, or a transition from work to “home.” I’m asking you to do a total of only three minutes of full-out exercise. Surely you can do that, can’t you? You could just jump rope or do jumping jacks, theoretically. It really is doable—so just do it! Start today. Stand up, step away from your desk and do jumping squats until you’re short of breath, and then sit back down. That is the feeling you want. Don’t try this at a staff meeting.

Finally, I’d like to share my personal work-break routine which I find simply transformative from both a physical and mental perspective. I made a great investment in my health with the purchase of a far-infrared sauna. I’ll be writing about the benefits soon, but it’s a great detox and mitochondrial booster too. You can get a less expensive version as a mat or tent. Here is what I do for an hour instead of having a coffee break.

  1. FIR sauna for 22 minutes maxing out at 130 degrees.
  2. HIIT with a dive into the lap pool for 18 laps (6 HIIT’s) + 20 leisurely laps (because I love to swim).
  3. Hot shower with final 30 seconds as a cold blast to get every last mitochondria that hasn’t been stimulated.
  4. Snack with some mitochondrial supplements. (Snack is usually 3 scrambled eggs with lots of healthy fat; grass-fed ghee).

What I’m suggesting here is that you can be creative with your HIIT session. You can make it short and sweet with simply doing the HIIT, or build on it before and after. The choice is yours. Get familiar with what feels as if it sharpens your mind. If your brain feels good, you are doing something good for your body and your brain; that’s how the current research is flowing. Just do it!

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