HIIT vs LISS Cardio | Which Burns More Fat?

Did the top stop spinning at the end of Inception?  Should you break apart an Oreo or bite into the whole thing?  Could the door have supported both Jack and Rose?!  I love debating.  Jenae and I took the “16 Personalities” test last month.  Was I surprised that my result was The Debater?  My husband sure wasn’t.  So my personality is defined as the “ultimate devil’s advocate”…. sue me.

One of my favorite debates is the widely popular HIIT vs LISS discussion.  Allow me to preface that while I currently perform neither, both forms of cardio are effective and beneficial for a multitude of different reasons… but the keyword is different.  What might be best for improving your VO2 max might not be best for getting you “summer ready,” but more on that later.  Let’s start with some basic definitions.  Below is a list I’m pulling straight from my article on whether cardio is helping or hurting your weight-loss goals (link here).

High Intensity Interval Training [HIIT]:

  • Short bursts of all-out anaerobic work, followed by rest periods
  • Large fluctuations in heart rate
  • Creates metabolic adaptions (increases your metabolism), as long as you are reaching your anaerobic and lactate thresholds
  • Induces a 24 hour boost in metabolism
  • Taps into abdominal fat storage
  • Increases mitochondrial capacity (where ATP is produced and fat is burned)
  • Allows retention and even increases in muscle mass, as long as cardio mimics multi-joint exercises with plenty of hip flexion

Low Intensity Steady State [LISS]:

  • Consistent period of work at a low to moderate intensity
  • No fluctuations in heart rate
  • Creates no metabolic adaptions, and even tends to slow the metabolism
  • Burns calories only in the given period of cardio, as opposed to the HIIT “after-burn”

If you’re looking to lose some weight and keep it off, it is my opinion that you should look for 3 major criteria from your cardio:

1. Ability to Burn Fat

Let’s talk about something we all remember from high school: mitochondria.  Everyone say it together now- mitochondria is the powerhouse of the cell.  It’s also where ATP is produced and fat is oxidized (burned).  We all want to be fat-burning machines, right?  To make that possible, you want a LARGE mitochondrial capacity.  That’s where HIIT cardio comes in and gives us superpowers- it actually increases that capacity, while zero studies show that LISS cardio does the same.

Speaking of ATP production, I’ve got two more science terms for you: anaerobic threshold (AT) and lactate threshold (LT).  When you reach these thresholds, you have gotten to the level where blood lactate accumulates above resting levels, resulting in greater ATP production.  More ATP produced = more fat burned.  These thresholds are only possible through short bursts of anaerobic work… aka HIIT cardio.

Plain and simple, HIIT is more efficient at burning fat.

2. Ability to Keep Metabolic Rate as High as Possible

So what is this 24 hour boost in metabolism that HIIT cardio allegedly brings?  This phenomenon is made possible through staying above the two thresholds mentioned above.  Okay so how do you know if you’re reaching those thresholds?  While you can actually get yours tested in a lab while performing anaerobic work, an easier test is whether or not you can talk during your work intervals.  I wish I could tell you it’s easy to get there… but it takes work, and this is where I see major discrepancies in the fitness industry.  A lot of people aren’t willing to reach maximum capacity.

Making your rest periods a priority ensures that you can perform at that maximum capacity for the next interval

Work as hard as you can for 10-30 seconds, then take 2-3 minutes (or more) to recover. Yes, it is possible that you could be at the level of fitness where you don’t need 3 minutes to recover. The test? How long does your heart rate take to go back down? I don’t know about y’all, but my heart feels like it’s exploding out of my chest well beyond the first minute of recovery.

A huge mistake I see is people performing “HIIT cardio,” and their rest intervals are less than 30 seconds??  Or even worse, their work time is larger than their rest time, such as 20 seconds of work and 10 seconds of rest.  You can keep calling it HIIT, but that my friend is called tabata. Tabata is a highly effective training principle nonetheless, but it’s effectiveness lies in it’s ability to improve your VO2 max… not burn fat.  Fat loss may occur, but save the tabata for that half-marathon you’ve always wanted to accomplish!  If you want to get serious about metabolic adaptions and therefore fat loss, increase the rest time and shorten the work time so you can put the high in high intensity am I right?! (*crickets*)

3. Ability to Retain Muscle Mass

More muscle mass = the ability to have a higher metabolic rate.  Multiple studies have shown that HIIT cardio retains muscle more efficiently than LISS cardio.  HIIT cardio even has the ability to increase muscle mass!

Have you ever looked at an endurance runner and a sprinter side by side?  Greater hip flexion = more muscle fibers engaged = more muscle fiber growth.  I’ve heard girls say they built their booty by walking on the stair master or incline on the treadmill.  While there is nothing inherently wrong with these exercises, that is not how you built a booty. HIP FLEXION. RAPID CONTRACTIONS.  POWER. Those are key.

Wrapping things up, HIIT cardio is by far superior for fat loss when compared with LISS cardio.  Thank you for stopping by and reading!  Subscribe to our blog for fitness & nutrition posts every week:)



1. Trembalay, A., et al. “Impact of exercise intensity on body fatness and skeletal muscle metabolism.” Metabolism, 1994; 43(7): 814-8.

2. Lemon, P. W., et al. ” Run sprint interval training improves aerobic performance but not max cardio output.” Med Sci Sports Exerc. 2011 Jan;43(1):115-22.

3. Zuniga, J. M., et al.  “Physiological responses during interval training with different intensities and duration of exercise.” Journal of Strength and Conditioning Research; May 2011; 25(5): 1279-1284.


  1. Avatar

    I simply could not leave your website before suggesting that I actually enjoyed the standard information a person supply for your visitors? Is going to be back incessantly to check out new posts.

  2. Avatar
  3. Avatar
  4. Avatar
    ETIAS Visa

    I’d like to thank you for the efforts you’ve put in penning this blog.
    I really hope to view the same high-grade content by you in the future as well.

    In truth, your creative writing abilities has motivated me
    to get my own, personal site now 😉

  5. Avatar
  6. Avatar
  7. Avatar
  8. Avatar
  9. Avatar
  10. Avatar
  11. Avatar
  12. Avatar
  13. Avatar
  14. Avatar
  15. Avatar
  16. Avatar
  17. Avatar
  18. Avatar
  19. Avatar
  20. Avatar
  21. Avatar
  22. Avatar
  23. Avatar
  24. Avatar
  25. Avatar
  26. Avatar
  27. Avatar
    canadian pharmacy

    I was just searching for this information for some time. After 6 hours of continuous Googleing, finally I got it in your site. I wonder what is the lack of Google strategy that do not rank this type of informative websites in top of the list. Usually the top websites are full of garbage.

  28. Avatar
  29. Avatar
    pharmacy cheap no prescription

    One more thing. I think that there are numerous travel insurance sites of dependable companies that allow you enter your vacation details and have you the estimates. You can also purchase the particular international holiday insurance policy on the net by using your credit card. All you have to do is usually to enter your own travel specifics and you can be aware of the plans side-by-side. Merely find the program that suits your financial allowance and needs and after that use your bank credit card to buy that. Travel insurance on the web is a good way to start looking for a reliable company for international holiday insurance. Thanks for discussing your ideas.

  30. Avatar
  31. Avatar
    bath fizzies

    Admiring the dedication you put into your blog and
    detailed information you offer. It’s awesome to come across a blog every once in a
    while that isn’t the same unwanted rehashed material.
    Great read! I’ve bookmarked your site and I’m including your RSS feeds to my Google account.

  32. Avatar
    buy viagra usa

    When I initially commented I clicked the “Notify me when new comments are added” checkbox and now each time a comment is added I get four emails with the same comment. Is there any way you can remove me from that service? Many thanks!

  33. Avatar
  34. Avatar
  35. Avatar
  36. Avatar
  37. Avatar
  38. Avatar
  39. Avatar
  40. Avatar
  41. Avatar
  42. Avatar
    dutch women viagra

    Hey would you mind sharing which blog platform you’re using? I’m planning to start my own blog in the near future but I’m having a difficult time deciding between BlogEngine/Wordpress/B2evolution and Drupal. The reason I ask is because your design and style seems different then most blogs and I’m looking for something completely unique. P.S Sorry for being off-topic but I had to ask!

  43. Avatar
  44. Avatar
  45. Avatar
  46. Avatar
  47. Avatar

    Great beat ! I wish to apprentice while you amend your web site, how could i subscribe
    for a blog web site? The account helped me a acceptable deal.
    I had been a little bit acquainted of this your broadcast offered bright clear concept

  48. Avatar
  49. Avatar

Leave a Reply to Anonymous Cancel reply

Your email address will not be published. Required fields are marked *