After hitting a training plateau with low-intensity, long duration cardio, I started doing some research and discover hiit. The web has been a great source of information - but it is varying information regarding the length of each high intensity session and each rest session, and the intensity of the session. I’m a 25 year old female, 5′7″ and 150 pounds – size 6/8.
Since staring HIIT 2 months ago, I have undoubtedly burned fat and built a lot of muscle. I’ve tried not to pay a lot of attention to the scale as I know my muscle mass has greatly increased. I’m pretty solid, but still have some fat that I want to get rid of that’s not coming off.

This is my workout: Hiit 3 times a week - alternate days. Elliptical twice a week- 3 miles in 38 minutes - more for endurance and toning my legs. I also do some ab & arm exercises 4-5 days a week.

I’ve read conflicting reports that my hiit workout is good, and others say it’s either “too long in session duration” “too long in total duration” “not intense enough”, etc. This is what I do:

Warm up for 7 minutes, start walking 4.2 mph up to jogging 5 mph at 2% incline.

Then Hiit Session 1:
1 minute running 7 mph at 3% incline – heart rate gets up to 170-180 bpm 2 minute cooldown jogging 5 mph at 2% incline – heart rate stays around 140-150 bpm.

Hiit Session 2:
1 minute running 8 mph at 1% incline – heart rate gets to 180 bpm 2 minute cooldown jogging 5 mph at 2% incline – heart rate stays around 140-150 bpm

Hiit Session 3:
1 minute jogging 6 mph at 5% incline – heart rate gets up to 170-180 bpm 2 minute cooldown jogging 5 mph at 2% incline – heart rate stays around 140-150 bpm

I repeat these 3 sessions again, and then session 1 again – totaling 21 minutes of “hiit”

I then usually spend a ½ mile cooling down. By the time I’m done, the workout has taken me about 35 minutes and my finished heart rate is still around 135 bpm. And while I am tired, I am not to the point of feeling like I’m going to throw up, like some sites suggest.

What kind of advice can you offer me? Do I need to shorten my sessions? Although the intensity doesn’t seem real high compared to what some other people do (12 mph, etc), my heart rate is still getting up there. Thanks for your help. Your site is great!

Jaclyn

Hello Jaclyn, thanks for the question.

First of all, punching the numbers into the HIIT Calculator you can see that you should be hitting about 175bpm in your high intervals and around 125bpm in your active rest intervals. You are definitely doing well to get to 180bpm, however I think this is due to the fact that your active rest heart rate is too high but I will address that shortly.

I think you should get off the treadmill and onto a spin bike for your HIIT, or if you must run take it outside to the track. The problem with the treadmill is it makes it a little too easy to run, and you can’t get that explosive burst of speed you really need for your high intervals. All treadmills take a little time to get up/down to speed, if they didn’t they would throw you off!

Besides switching equipment, I think your intervals need to be scaled down. Your interval ratio is 1:2 and this is generally fine, but your intervals are probably too long to be doing every session. Try 30 second sprints with 45 or 60 second active rest periods. Don’t forget variety is the spice of life and some days you can even try a 15/30 split or go back to your 1/2 minute intervals. We need to keep our bodies guessing for best performance gains.

Your active rest intervals at this stage are only 1-3mph slower than your high intensity intervals and this is causing your heart rate to stay too high. I’m hoping after this you will get onto a spin bike or at least somehow off the treadmill. You need to slow your active rest intervals down to walking pace to make sure you get back down to ~125bpm. By doing this you will also be able to take your interval ratio to more like 2:3 or a 30/45 second split.

As for total duration of your HIIT workouts, go for as long as you can but if you find you are going above 20 minutes, especially with these shorter intervals I am proposing, then you need to bump up your intensity. This 20 minutes does not need to include your warm up or cool down - which by the way is great to see you are doing.

If you can warm up, do your HIIT for 15 minutes, then attempt a cool down before collapsing on the closest soft chair, then you’re doing alright

If you have a question about HIIT please use the contact form and I will do everything I can to get you the information you need.