More Proof – HIIT Better than Cardio

I-LOVE-HIITAs a personal trainer with 25 yrs of experience AND as a certified fitness junkie, I love HIIT because…

  1. it works really, really well to help my clients get fit really, really fast,
  2. it helps my clients drop excess body-fat really, really fast
  3. and because it is really simple to program HIIT workouts and it fits into the busiest of schedules really, really well.

Unfortunately, not everyone sees HIIT like I do. 

There is a large group of trainers and fitness “experts” who…

  • think that low intensity cardio is superior to HIIT for developing aerobic fitness, and
  • fear that the High Intensity aspect of HIIT is dangerous to the health of their clients.

Their concern is that people with less than perfect cardiac function are at imminent risk of suffering a heart attack if their trainer puts them on a HIIT protocol. Which makes sense….if you haven’t read a medical journal in the past few years and still believe that low intensity cardio is the only safe way to improve cardiac function..

However, if you’re like me and don’t want to wait for our mainstream health & fitness to catch up with modern science, I invite you to…

1. Take a look at some of my articles about HIIT and Cardiac Function

2.  Take a look at the latest research investigating HIIT and building a healthy heart

In a study just published in the Journal of Science and Medicine in Sport, researchers tested the effectiveness of HIIT workouts to improve the VO2max/VO2peak of 112 patients with coronary heart disease.

NoteVO2max/VO2peak is considered to be the gold standard for aerobic fitness, and aerobic fitness is believed to be the best indicator of cardiovascular health and a well-established predictor of total and cardiovascular mortality in subjects with and without coronary heart disease.

This means that exercise protocols which drastically improve VO2max/VO2peak are to be seen as powerful tools to help the medical (and fitness) communities prevent coronary heart disease and extend life.

In this study, the participants were divided into three groups based upon exercise intensity – as determined by percentage of HRmax.

  • <88%,
  • 88–92%, and
  • >92% of HRmax

The goal of the study was to determine if higher relative intensity during exercise intervals would elicit a greater
increase in VO2peak…leading to greater & faster improvements in aerobic fitness and in theory improve cardiac related mortality rates.

Here’s what happened

  • No adverse effects occurred during training
  • Overall, VO2peak increased by 11.9 % after 23.4 exercise sessions
  • Higher intensity exercise groups showed the greatest increase in VO2peak
  • 3.1 mL for the <88% group
  • 3.6 mL for the 88–92% group, and
  • 5.2 mL,for the >92% of HRmax group

hiit heart function

These findings build upon previous research which shows that the beneficial cardiovascular effects of aerobic exercise are intensity dependent, with higher intensity exercise showing a superior effect…leading the study authors to conclude that  “CHD patients who are able to perform high intensity training should aim at increasing exercise intensity above 92% of HRmax and thereby possibly achieve even greater improvements in aerobic capacity”.

What does this mean for you?

  • If you’re a CHD patient, you need to talk to your cardiologist about HIIT training…keeping in mind of course that CHD patients need to keep a close eye on how everything they do – exercise, nutrition, lifestyle, stress, etc – can impact the function of their CV system.
  • If you’re not a CHD patient, it means that if you want to improve your aerobic fitness and avoid dropping dead of a heart attack, you NEED to start doing some form of HIIT – High Intensity Interval Training.
  • And if you’re a doctor or fitness expert who still believes that low intensity cardio is the best way to improve aerobic function, you need to put down your preconceptions and pick up a scientific journal every now and then.


  • Moholdt T, et al. The higher the better? Interval training intensity in coronary heart disease. J Sci Med Sport
  • Rognmo O, Moholdt T, Bakken H et al. Cardiovascular risk of high- versus
    moderate-intensity aerobic exercise in coronary heart disease patients. Circulation 2012; 126(12):1436–1440.
  • . Kodama S, Saito K, Tanaka S et al. Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women: a meta-analysis. JAMA 2009; 301(19):2024–2035.

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  1. Hey DR, love the posts but I’ve got a question. Have you seen (or could you recommend) a starting HIIT program for someone who had a heart attack 2 years ago? I know, I know must consult a doctor as well, etc. But just an idea of a starting program would be appreciated.

    It would be for a 55 year old woman who has been doing low/moderate intensity slow-go cardio 1-2 times per week for the past year or so. I’d greatly appreciate your input, thanks!

  2. Hey Mike

    First off, thanks for throwing in the doctor caveat.

    Whenever I get a compromised client like yours, I try to hammer home the idea to them that HIIT is relative to their current level of fitness. Their “high intensity” is different than yours or mine. For example, I have a lady who can sprint now, but when she started…her HIIT was a slow jog : walk combo.

    Another thing you want to address is workout volume. Instead of trying to fit all of her HIIT into a scheduled 60 minute workout, it is better for her to space out mini-workouts throughout the day. I would call/text her throughout the day to get her to do 2 minutes of HIIT (10 sec jog : 50 sec walk). Eventually, she got used to doing it and was able to self-monitor. She set a timer on her phone for an hourly HIIT 2 min session.

    For her formal workouts, I would suggest throwing 5 and 10 sec sprints into her slow cardio workouts. Keep the resistance low…focus more on speed than resistance. Also, I would suggest having her try to count revolutions per sprint. Pay attention to one foot and count the number of times it hits the extended portion of the cycling stroke. This gives you a positive and measureable to keep her pushing a little harder. If she does 20 revs per 10 sec at the start…you can keep pushing her to get 21…it’s a minute progression and totally achievable as her energy systems become more efficient.

    Hope this helps

    Add 10:50 and 5:25 sec sprints into her cardio workouts
    Schedule mini-HIIT-workouts throughout the day – 2 x 10:50s or 4 x 5:25 – these could be sprint:jogs or running in place or jumping jacks or step-ups on the stairs in her home

    Also, remember that you want her sprints to always be fast (relative to her fitness). When she gets tired and isn’t recovering and her fast is getting less and less fast…end the workout….or extend the rest periods if you really want to get a few more sprints done.

    Hit me back if you have more questions…I realize my answer rambled a bit

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