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The Truth Behind HIIT Cardiovascular Exercise

September 15th, 2009 · 21 Comments ·


I admit that I did not do any cardiovascular exercise when I first started doing weight training. For me that time, cardio was just too slow and too easy. I rather do another few sets of bicep curl or bench press than running on treadmill. Low intensity aerobic training was intolerable, worse than watching slow pace of golf on television. I wanted only action with more challenge.

However, like it or not, no matter how much weight I lift, to reveal the 6-pack abs, I realize cardio is still a must to burn the stubborn fat. In fact, the more I learn about cardio, the more I know about its importance. Cardiovascular exercise does not have to be done in only one monotonous way. Despite what I recommend you to try on low intensity cardio, today, let me share with you – high intensity cardio training with short intervals of rest in between (HIIT).

What Is HIIT?
HIIT stands for High Intensity Interval Training. Some people call it Power Cardio. Instead of doing long hours of lower intensity of cardiovascular exercise, some studies have shown that HIIT actually burns more fat. HIIT is an exercise approach to improve performance with short training sessions with several intervals.

It increases the metabolism rate even after the exercise due to excess post-exercise oxygen consumption.

Why HIIT May Be Better Than Lower Intensity Training?

  1. In low intensity exercise (which your heart rate is about 65% of your max heart rate), assuming you burn about 100 calories for energy while training. Out of 100 calories, as much as 50% or 50 calories are from fat and others are from carbohydrates or protein. On the other hand, high intensity training will use about 40% of fat as fuel. Now, if you just want to burn fat, low intensity exercise appears to be a better choice with higher percentage of fat burnt. However, low intensity training burns fat calories only during the time you are exercising. As soon as you stop your workout, the fat burning stops. In contrast, high intentisty training will spike your metabolism and keep it at high level for the rest of the day, as long as 24 hours, even after you stop the activity. In other words, you continue to burn fat all day long and end up burning more fat. With HIIT training, the majority of calories burned will come after your workout. You consume more oxygen recovering from the exercise than you would have if you just did a low intensity steady state of cardio.
  2. While trying to recover between interval, your aerobic system (including your heart and lungs) work hard to overcome the oxygen debt. Therefore, your cardiovascular system will improve.
  3. Because you are doing high intensity exercise, you normally spend only about 15 minutes whereas you may spend 30 to 60 minutes if you are running or cycling slowly. Shorter workout period means you save time.
  4. If you only do low intensity for the past 1 year, your body may have gone into a steady to conserve calories. So, program like HIIT may give your body a “shock” and allows it to burn more calories.
  5. Not only HIIT burn calories, it increases your speed and endurance. That’s why athletes see better gains from doing HIIT cardio compared with traditional cardio. Sports like soccer, rugby, basketball or tennis have the moment that you need to change speeds.


How You Can Perform HIIT?
HIIT training can be applied to many activities, whether indoor or outdoor. You can try doing HITT on elliptical, stationary bike or stair climber if you are exercising indoor. However, HIIT will be more suitable for outdoor running or sprinting. As long as you can alternate periods of high intensity with periods of low intensity.

I will use running as an example, but the same concept applies to other cardio exercise.

  1. Start with a warm up jog for about 5 minutes.
  2. Once you are warmed up, increase your intensity by running at your top speed for about 30 seconds. During this stage, run as fast as you can and you should feel the burning sensation in your muscles.
  3. After that, slow down by jogging, then stop your movement totally. You should spend about 1 minute at this stage.
  4. Once the minute is up, run again at high speed for 30 seconds. Continue to do step 2 and 3 for 5 to 15 minutes depending on your fitness level.
  5. After you finish, cool down by doing some stretching.


Other HIIT examples:

  • If you are on elliptical trainer or bike, change your speed and intensity level every 2 minutes or so, up and down, to challenge yourself. The concept behind this variation is to trick your body to burn more calories since it cannot achieve a steady state.
  • Another option will be running uphill. Say, you take 20 seconds to reach the top, then you can walk down serving as your rest interval. Then, run up to the hill again. You can repeat several times before you jog back home as a cool down.

As of how often should you do HIIT, I would say 2 to 3 sessions a week is sufficient to produce significant fat burning effect. Just like other activities, do not overtrain or overdo. I normally do it during my weight training off days.


Avoid HIIT Cardio On Treadmill Though…
I have tried doing HIIT on treadmill and I found that it is impossible to do so. No doubt, running on treadmill is probably the most popular cardio but unfortunately it is not suitable for HITT. When you accelerate to your top speed in short interval and then decelerate to much slower speed after that, the changes of speed is limited by the treadmill. It is not able to go from 2.5 mph to 10 mph in short interval and vice versa. If you want to slow down from your top speed, you may slip and fall.

In fact, treadmill may be too slow for HIIT for some people. It may hinder your full capability to go for the highest intensity level which is necessary for HIIT.

Before You Try HIIT…

  • If you are overweight or just started to do exercise, HIIT may not be suitable for you. Exercise at lower intensity is safer and easier for you. As a beginner, I do not recommend you to try something so challenging because you may not like it. If you do not like it, you will not stick with it.
  • HIIT is tough. When you finish, you may feel like throwing up. So, do not aim for a 15-minute HIIT. For beginner, if you can complete 5-minute HIIT, it is good enough.
  • Bear in mind that if you end goal is to slim down, you still need to eat right and do resistance training to see the result. If you eat more than what you burn, HIIT will not give you much improvement.
  • No matter how good you think you are, always warm up to get your heart and muscles ready.


Last Words
Though HIIT seems to be take less of your time, HIIT is not easy. It is physically demanding. HIIT is meant for people whose primary concerns are boosting overall cardiovascular fitness and fat loss without losing muscle mass they already have.

Also, you do not have to replace all your low intensity aerobic exercises with HIIT. A good balance, for instance, 2 sessions of HIIT per week with 2 sessions of low intensity cardio, is recommended.

For those who have tried HIIT, I would like to hear from you. Leave your comment here. Cheers.



Category: Other Fitness/Sports Articles

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21 responses so far ↓
  • Juha Liikala // Sep 15, 2009 at 7:53 PM

    Great article! I’ve done HIIT in combination with full body workouts and love it! I’ve kept my routine somewhat like this:

    Mon: FBW (Full body workout)
    Tue: HIIT (15 minutes)
    Wed: FBW
    Thu: Off day
    Fri: FBW
    Sat: HIIT (15 minutes)
    Sun: Off day

    I’m doing HIIT 2 times per week and I find it sufficient for my fitness level. Before I started doing HIIT, I did regular cardio for a year. After that I started doing 10 minute long HIIT exercises. Today I usually do 15-20 minutes and it’s more than enough to get yourself exhausted but happy when the exercise is over! The only difference in my HIIT routine (compared to the one mentioned on this page) is that I don’t completely stop in between running intervals. Instead I stop running and walk for a one minute. Then I do the sprint phase again.

    Thanks again for reminding people about the benefits of HIIT! Keep it up :)

  • kennymah // Sep 15, 2009 at 8:08 PM

    Less time and more intensity? Sounds like the recipe for a good workout to me! :)

    But more importantly, I like your final words on how to balance it off with some low-intensity cardio workout too. For some of us, that might some light jogging on the weekends with family and friends. Let’s not forget fitness can be both a personal challenge and a social focus. :)

  • Teddy // Sep 15, 2009 at 8:51 PM

    I have been following your blog for quite some time now. I have to admit that I enjoy reading your blog very much.
    I want to add that for many cardio-exercise equipment nowadays, there are several functions or mode of exercises to choose. I noted that equipments with “Fat-Burning” options, the pattern of exercising is actually HIIT with intervals of high and low intensity.

  • Cynthia // Sep 15, 2009 at 9:46 PM

    I LOVE HIIT. For me, it really is the best option..When I do my long run outside, I always use it..1. It makes the time go much faster. 2. I see results. I am the classic slow metabolism girl. I trained for my first 1/2 marathon in the traditional sense and lost 4lbs…I trained for my 2nd using HIIT and I lost 14lbs over the 12 weeks. I know that there are studies out there to contradict the basis of this training, but I learned long ago, that NOTHING is the end/all for everyone. Utilize what works for you! This does it for me…and a lot of my clients as well:)

  • Austin // Sep 15, 2009 at 10:21 PM

    There are treadmills where the running speeds are pre set at the touch of a button, making HIIT more effective. I agree that some treadmills change speed pretty slow but it depends on the type of treadmills your gym has. In fact doing HIIT on the treadmill works the best of me.

  • Eric // Sep 15, 2009 at 10:57 PM

    I’ve been doing HIIT the past 2 months. I notice between HIIT & 1 hr steady walk on the treadmill is that I am more hungry after the workout. So I have my usual oatmeal or cereal in the morning. It’s a good charge to my body.

  • foongpc // Sep 15, 2009 at 11:43 PM

    I find HIIT very demanding but it certainly saves a lot of time! Although you mentioned it is not for beginners, I think beginners can still incorporate HIIT in their aerobic exercises.

    They just need to take it at a lower intensity and take more rest time in between.

    Eg. Instead of running as fast as possible for 30 seconds and then slow down for 1 minute, and repeat the cycle, the beginner can jog for just 20 seconds, and then walk slowly for 2 minutes, then repeat the cycle a few times.

    Once his fitness improves, he can then try running as fast as he can for 10 seconds, and rest for 2 minutes, then repeat the cycle a few times.

    When his fitness continues to improve, he can increase the duration of the high intensity run and reduce the slow intensity walk to continually challenge himself.

  • Ryan // Sep 16, 2009 at 2:47 AM

    I couldn’t agree more… cardio is key. HIIT is great also, but damn tough. The best is to make sure you’re doing what you enjoy most be running on a treadmill or out in the fresh air cycling. I do HIIT while commuting on my fixed gear bike – love it!

  • Jonz // Sep 16, 2009 at 9:34 AM

    I’m doing HIIT for the past couple of months now. I do about 2-3 sessions a week with some variations of it on the treadmill.

    1.) As usual, warm up for 2 mins of brisk walk at 5.5 and then 2 mins of running at 13.0 or 13.5. Repeat for about 3 – 4 sets.

    2.) As usual, warm up for 2 mins of brisk walk at 5.5 and then 1 mins of running at 13.0 or 13.5 and 1 min of brisk walk at 5.5. Repeat for about 6 – 7 sets.

    The above will take approximately 20 mins inclusive of cool down time of about 3 – 4 mins.

    I do my HIIT after my weight lifting session where I train 2 muscle groups each day or on my off days. I spend a maximum 1 hour +-10 mins in the gym each time.

    Incorporating HIIT into my routine these past 3 months has allowed me to drop my body fat effectively by about 5% now, now i’m at about 15%, target aim is at 10%. I have managed to maintain or increase my muscle mass at this moment of time as well.

    Of course all the above are done with a manageable and healthy diet.

    As I’m someone in the corporate world and therefore time is of essence, I stretch my goals longer but ultimately achievable.

  • surfnux // Sep 16, 2009 at 11:27 AM

    Thanks for the sharing and motivation man, I gonna try to get back to Weight training routine plus a cardio workout just to gain back 6 Kgs I have gained in the past 1 year from being back to a suburbia for good.

    Switching from working for people to Entrepreneur for the past 1 year period has caused me a lot of up and down in trying my best to exercise. And I failed a lot. There isn’t just any great gym here like Fitness First which I normally go for while in Singapore. Gyms here are plain normal, with air conditioning served as a display ONLY, and not put into use. Its pretty stuffy and that prevents me from going anymore. Stuffy and people peek at you most of the time. Not like any gyms which I use to go with everyone focussing on their own workout rather than spotting what other people’s are doing.

    Working out from home is another option I tried, got my self a pair of dumbells, skipping rope, a basketball with my own private court, and sometimes I combined them with shadow punching from moves I learnt in Body Combat. But I got it failed after two to three days of working on this. Its either boring, or I feel too tired every evening after sitting in front of my notebook working.

    I think I really need a workout buddy who share the same goals and a big motivation to stay constant.

  • Jesse Regan // Sep 16, 2009 at 5:00 PM

    I would say you have to increase the intervals when you increase the intensity in any cardiovascular exercise. For me, I can’t neglect it.

  • gagreflex // Sep 16, 2009 at 6:20 PM

    HIIT or rather, sprint training has improved my fitness by tonnes…

    This is a typical full-blown HIIT session for me:

    sprint 100m
    lunge 30m
    20 squats
    4x20m shuttle run
    10 pull ups
    1 min of box jumps

    now that’s one set.

  • Maurice // Sep 21, 2009 at 7:27 AM

    Like the way you showed how you began to realise the value of cardio routines to your regime. The best thing about cardio for me is the endurance factor.

  • Paul // Oct 21, 2009 at 11:04 PM

    High heart rate exercise is very important. Take stair running ir sprints for 10 minutes and it will increase your long distance running ability due to the cardio vascular development it stimulates.

  • boldtrends // Oct 22, 2009 at 1:37 AM

    This type of exercise works and is the basis for a great workout and all round fitness.

  • OneHIITChunder // Mar 25, 2010 at 11:13 AM

    I tried HIIT for the first time today on the stationary bike, as follows

    15 minute jog (was meant to be a warm up but got carried away)

    60 secs low intensity cycling (about 80 rpm)
    30 secs all out (about 125 rpm)

    Repeated this cycle for five minutes. As the burn set in, I began lowering the resistance to enable me to keep going during the all out phase. I started at level 10, and reduced in increments of one until I had done ten minutes in total.

    I then felt incredibly ill and threw up about twenty minutes later! Was fine shortly after.

    Actually looking forward to training more this way, minus the vom.

  • Shane // Apr 22, 2010 at 12:25 AM

    Cool article! I’ve been reading a lot about HIIT lately and I definitely want to try doing this instead of the usual, steady running.
    I plan to start with my first bout of HIIT next week. Hope my knees will cooperate! :)

  • zane // May 15, 2010 at 9:55 PM

    I have started doing HIIT around 2 months ago.

    Previously I used to do slow jogs for 50-55 mins and did about 16 miles per week but without any effect on my belly fat even after 2 years of this regimen.

    However I have noticed some marked improvements with HIIT and intend to continue training like this even if it is actually harder than the slow jogs. I feel light headed after my morning sessions and need 15 minutes rest and plenty of water to get back to normal.

  • GN // May 21, 2010 at 12:35 PM

    This month i am performing HIIT 6days a week.
    I have been a pack a day smoker for the last few months to a year, just recently quit.

    I am in my 3rd week, and I have seen HUGE improvements in my training, i am getting stronger by the workout (according to my log).

    Mondays, wednesdays, and fridays; shadow boxing with 15lb dumbells in each hand for 15-20secs, followed by 45-60 sec rest FOR ONLY 6 REPETITIONS.
    On these days I also do a short intense weight sessions (total sets of 12)

    Tuesdays,thursdays, saturdays.
    I alternate between stationary bike HIIT (30secs, 20secs,15secs repeated x2 with a rest period of 30 and 60secs),
    and stair sprints with a 30lb weight bag (4levels for 6 cycles).

    I WORKED UP TO THIS LEVEL BY THE THIRD WEEK, I STARTED WITH 4CYCLES ON EACH WORKOUT. i dont plan on adding cycles since i am doing it 6x a week.

    tell me what you guys think about this workout.

  • Mediamonk // Jun 28, 2010 at 2:37 PM

    This is my second foray into HIIT. For sure it works, but you have to be careful not to overtrain. That was my mistake the first time.

    I tried to do HIIT everyday, in addition to strength sessions. Started dreading the gym, and after a couple of weeks I fell sick.

    Now, I do HIIT 3 times a week and 60 min Cardio in between, in addition to a single HIT strength session (my goal is not so much to gain muscle mass, just not to lose any) Enjoy my sessions more and consistency is the key.

    Typical HIIT workout for me on the stationary bike is 30 sec all out, 30 sec rest x 3-4 to get my heart racing, then 30 sec all out 60 sec rest x 4-6. I haven’t thrown up yet, but it damn near kills me. After showering and changing, 15 minutes later and I’m still a little breathless.

    Noticeable fat loss. Minimal muscle loss. Thumbs up to HIIT. But know your body and watch out for overtraining!

  • jason // Mar 25, 2011 at 9:14 PM

    I started HIIT at 247 lbs. My 1st 3 wks I lost 18 lbs & then 5-10 lbs every month until I got as low as 179 lbs. in about 10 mths. The other thing to mention is metabolism. I was HUNGRY every 2 hrs no matter how much or little I eat earlier. Be ready for this by having pre determined snacks or meals. Already grilled chicken, fish or pork, steamer veggies, small amounts of mixed nuts, salads, etc are all good. Also, don’t deprive. If you want pizza or taco bell, eat it. Just know the nutrition facts beforehand & drink water before eating. I found higher protein to work for me until I got to my desired weight & then added more good carbs. HIIT works, but it’s not for the faint of heart! If you love the intensity & are OK with feeling like you got your butt kicked afterwards, GO FOR IT! Be patient, this isn’t an overnight solution! If you want 20 lbs gone this week, too bad. If you want 20 lbs gone in 2 mths, more likely. Commit to a lifestyle, have a friend to help & your results will ROCK!!

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