High Intensity Intervals are Far Superior to Endurance Cardio

Male Sprinter

I don’t HATE endurance cardio. I’m trying to give it a chance, albeit a slim chance.

It has its purpose in workout routines, especially for those who are untrained, obese, or have health complications that make high intensity training dangerous. But I can’t just blow off the continually mounting evidence (for the past 15 years) that high intensity interval training is optimal for fat loss and for developing speed, power, muscle, and even endurance!

For many years now, hardcore trainers have been touting the superior effectiveness of high intensity intervals for fat loss. But still, trainers, athletes, housewives, couch potatoes, televangelists, martial arts instructors, teachers, doctors, and pretty much anyone outside of the ‘hardcore trainer’ group suggests that if you want to lose weight you have to either walk everyday or jog for at least an hour a day 4-5 times a week. Wake up people!

The Study

A new study by the Journal of Medicine and Science in Sports and Exercise compared two groups of athletes who performed either 30 second sprint intervals, or 30-60 minutes of endurance running at 65% max heart rate (MHR). The study lasted for 6 weeks. Each group increased total volume in that time period – the sprint group increased from 4 sprints with 4 minutes rest to 6 sprints, the endurance group increased from 30 minutes to 60 minutes per session by adding 15 minutes to their sessions every 2 weeks.

The Results

Fat lost by sprint intervals in 6 weeks: 12.4% body fat and an average of 5.5 lbs (2.5 kg) of fat mass.

Fat lost by endurance cardio is 6 weeks: an average of 1.1 lbs (.5 kg) of fat mass.

Total time spent actually sprinting in 6 weeks: 45 minutes

Total time spent on endurance cardio in 6 weeks: 13.5 hours

Am I trying to tell you that the endurance athletes spent 1800% more time running than the sprinters did? Yes I am!

Am I trying to tell you that the sprinters got 500% more results from 5.5% of the effort? Pretty much!

Am I trying to tell you that you are basically wasting your time by including endurance cardio in your workout? Yes! Why won’t you get it?!

By the way, even when you include the rest intervals, the sprint group still exercised for under 7 total hours compared to more than 13 hours for the endurance group. That’s still only half as much time taken out of your day for 5 times more results.

Female Sprinter

Why Do High Intensity Intervals Burn Fat so Much Better Than Steady-State Endurance Cardio?

We know that high intensity interval training elevates metabolism for up to 48 hours after exercise by dramatically increasing oxygen consumption. This means you expend more energy and burn more calories for the next 2 days just by sitting on the couch or at the computer.

Sprinting also burns a ton of calories in a short amount of time. There is some increased energy expenditure due to the total time spent performing endurance exercise, but it doesn’t compare to short, maximal effort burns you get from sprinting.

You know those enzymes that break down adipose tissue and fat molecules for use as energy? Well the metabolic processes that result from high intensity intervals increase those enzymes, which makes your body burn more fat instead of storing it away like a grizzly bear prepping for a long winter.

What About the Cardiovascular Benefits?

After 6 weeks, both groups increased their 2000 meter speed by an average of 5%. The cardiovascular demands of sprint intervals are so great, that they train you aerobically just as well as endurance cardio, but again in a shorter amount of time.

So if you are preparing for sub-marathon races like Run For Your Lives or the Spartan Race, instead of running 5 miles a day you should be using a mixture of:

  • high intensity intervals (sprints, jump rope, burpees)
  • plyometrics (jump squats, depth jumps, box jumps)
  • body weight resistance training (pull ups, muscle ups, chin ups, push ups)
  • and some regular weight training if you are into that sort of thing

Here are a couple examples of how to put together really effective interval sprint routines: The Very Best HIIT Routines for Fat Loss and Fitness.


Run for Your Lives

What you should have learned from this article, is that if you want to minimize time and maximize effectiveness, high intensity intervals are your best choice. Any kind of walking, jogging, or other endurance cardio is just a waste of your time, with few exceptions.

Keep in mind that there are some valid exceptions like injury, training experience, and so-on. Jogging could also be an option if you are already resistance training hard and frequently, using HIRT sessions, other HIIT sessions, and/or tabata training. You don’t want to overtrain anaerobically. But remember that if you are already training hard and frequently, and you are not seeing the fat loss results you want, THE PROBLEM IS PROBABLY WITH YOUR DIET!


Run sprint interval training improves aerobic performance but not maximal cardiac output.

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5 Responses to “High Intensity Intervals are Far Superior to Endurance Cardio”

    • Yes, HII Training is better for everything EXCEPT real marathons and triathlons, you know, that really long-long-long distance crap. To lose weight, gain muscle and or keep muscle you have already gained, then this is better. It creates more fast-twitch muscle fibers which builds speed and power. Watch a college track meet, especially the SEC, and take a look at the sprinters. Then compare marathon runners, slow twitch muscle that is. Plus long term endurance training has a strong catabolic effect on the body and muscle specifically. More muscle, more calories burned. If muscle is constantly breaking down from long term training, it becomes less effective at burning calories and maintaining strength. Load up on green tea, Vit C and alike antioxidants because when you start this type of training, it takes your body time to "adjust" which translates into "your ass is gonna hurt lik'a MU'TH'A'F'K'A". (spoken in my best Samuel L. Jackson)

      • Thanks for the comment Ric. I completely agree with your sentiments regarding marathons and triathlons. Using HIIT exclusively to train for extremely long distance activities, isn’t the best solution. Those folks need to actually train marathon/triathlon style to prepare for race day, or they’ll be in for a world of hurt. I do think it is a good idea to sprinkle in some HIIT training even for those folks, to facilitate an effective balance across the energy systems, but I haven’t really researched it and I’m no scientist, so I could be wrong.

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