HIIT will make you stronger, faster and leaner…..One of the ways it does that is by improving your lactate threshold (LT).

What is Lactate Threshold?

Lactate threshold is the level of exercise intensity where lactic acid builds up in your bloodstream and you begin to feel that lactic acid burn. In the world of athletic science, LT is usually expressed as a percentage of VO2 max.

What is VO2 Max?

VO2 max is defined as “the highest rate of oxygen consumption attainable during maximal or exhaustive exercise”

Essentially, it is a measurement of how much oxygen you can get into your muscles during exercise, and is widely accepted as the single best measure of cardiovascular fitness and maximal aerobic power.

The Magic of HIIT

So how does LT & VO2 Max make me stronger, faster, leaner?

  • If you can delay the build up of lactic acid in your blood, you can trainer longer, faster, harder.
  • If you can train longer, faster, harder, you will become stronger, faster leaner.

And how do we delay the lactic acid burn, increase our LT and maximize our VO2 max?

Well, according to this study, high intensity interval training significantly increases LT and VO2 max.

The Study

Researchers took 20 physically active individuals and put them through one of two separate 6 week training programs.

  1. Group 1 performed 1 interval training workout per week
  2. Group 2 performed 2 interval training workouts per week

After 6 weeks,

  1. Group 1 improved their LT by 4.3%
  2. Group 2 improved thei LT by 8.2%


Not only is interval training (HIIT) a successful strategy for improving LT and VO2 max, there is a dose-response relationship between frequency of interval training and the magnitude of LT improvement.

In other words,

  • if you increase your HIIT, you increase your LT
  • if you increase your LT, you increase your VO2 max
  • if you increase your LT & VO2 max, you get stronger & faster & leaner….

And who wouldn’t want to get stronger, faster & leaner?


  1. Great write up on an underused technique. I use HIIT frequently and it certainly does work. You’ll work your ass off whilst training, but the rewards are more than worth it.

    The best thing is that it can be applied to near anything! I might do 30 sec sprint/1min jog on the treadmill one day, then the same on the bike another day. Can be applied to weight training too – highly recommended to the many people who are desperate for quick results.

  2. I am living proof of live longer and better with “HIIT” habits.
    As a former golden glove boxer I was trained early using HIIT over 40 years ago. We didn’t call it anything but boxing routine back then.

    But it was really high intensity interval training

    You are right HIIT creates a health habit that can make anyone live longer and better. Yesterday at age 54 blood pressure 125/77 and I owe it all to the light routine I do 3 days a week, workouts I learned at age 14.
    Lets conquer child obesity this decade.!!!

  3. Doug,

    You are killin’ me with the pic of the kid with man-boobs! Great post though…and the picture does actually does inspire. I’ve done HIIT for years, but have never used a timer. I will check out your suggestion and maybe order a Gymboss interval timer like you recommend.

    -George D

  4. Great post once again. And might I add HIIT is less boring? Always a plus for me😉

    PS – I had to research to see what that stood for LOL – but I do this!

  5. I still wonder what the upper limit is for HIIT, can you do HIIT 3, 4, 5, 6?? times a week? When I have been in my “HIIT” groove the most I was doing was 3 official sessions a week, but I felt like I could do more, and probably was doing more considering some martial arts training is similar to HIIT (sparring, striking bags, even kata are fast and then slow at points) but I have always been concerned about over training. I would suspect when your reaching maximal heart rates, any over training is of more concern then just pushing more reps on a bar, but when I was in the “groove” I never felt like I was over training. Maybe HIIT is not really like weight lifting, the recovery is much faster?

  6. HIIT with weight training is what I find most effective for me. Getting on and nearing 40, I find that sprints are just too hard on the joints. I go to about 70% weight of what I can lift and up the repetitions with 30sec intervals. Great article, thank you.

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  9. I absolutely love HIIT. Cathe Friedrich & P90X have great HIIT workouts. I also love doing it on my Spinning bike – less stressful on the joints than doing it on the floor. If you have issues with the knees, you may also try using a “rebounder” or small trampoline – takes all the impact out of the move.

  10. I really wish someone could give me the name of the man in the photo. I have no doubts whatsoever about HIIT workouts being extremely effective but I can’t help but feeling that photo is fake. I can’t imagine his body fully snapping back from that weight. Not the right body make up to do so. Again, I am not doubting the validity of your post, just the photo. Can anyone give me his name and more info?

  11. hey Gabe – the pic is of 2 different people. It’s basically an eye catcher/attention grabber.

    btw, the guy on the right is an Olympic weightlifter

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