HIIT workouts

Unless you have been living under a rock for the past few years, you will doubtless have come across HIIT workoutHIIT training be it in the media, at your gym or over a conversation at the water cooler in between Bakeoff/Masterchef/GameofMarbles chitchat.

HIIT stands for High Intensity Interval Training and it has become the buzz workout of recent times promising to torch fat in record time, attach speed rockets to your metabolism and help create the fat-burning, ripped body you have always dreamed of. Bold claims. So is this hype or does this method of training really work?

I will explain the hows, whats and wherefores forthwith (m’lud).



HIIT comes in many guises (fartlek, tabata) but in essence this method of training comprises short, sharp work intervals followed by brief breaks until you either throw up or pass out. Ok, maybe I’m exaggerating the last bit. That said, a HIIT workout needs to be done correctly to reap the benefits it touts and most people get nowhere near the intensity required. Much like the fact that any weight loss diet will work if you stick to it, a HIIT workout can potentially do the following:

  • Improve heart health
  • Increase flow of oxygen & fuel into muscles
  • Increase fat oxidation
  • Improve carbohydrate sparing, i.e. increase in body’s ability to burn fat as fuel instead of carbs
  • Increased EPOC (Excess Post-Exercise Oxygen Consumption), i.e. oxygen consumption remains elevated post exercise session meaning ongoing calorie consumption whilst body works to restore homeostasis (return to equilibrium) 


Improve heart health


In addition to these benefits, HIIT training is also time efficient. An effective session can be over and done with in a matter of minutes. However, the key focus is the intensity level. You are looking to achieve your maximum effort, short recovery and then repeat.



Intensity levelsThe easiest & yet highly effective way of gauging your training intensity level is to use the PRE or Perceived Rate of Exertion method.  On a scale of 1 – 10, if 1 is lying in the couch with a glass of wine & 10 is beetroot-faced reaching for the bucket, you want to be nearer the bucket than the couch when doing HIIT.  8 or 9 is what you are aiming for, i.e. puffing hard & unable to hold a conversation.  It is highly individual as what feels like an 8 to one person will be quite different to another which is natural and normal. 

If you want a more mathematical and precise way of gauging your work intensity, I would suggest using a heart rate monitor.  You can use the treadmill or bike one but these are usually highly inaccurate.  They can however be a guide if you have nothing else.  If you have your own monitor then follow this age appropriate formula to estimate your maximum heart rate (MHR):

220 – your age x target intensity range (from 70 – 85%) = MHR

Choose your target intensity range (THR) according to how hard you want to work, e.g. 70-75% for tough, 75-80% for really tough & 80-85% for uber hard.  So, if you are 35 years old wishing to train like a demon, here is your formula:

220 – 35 = 185 (MHR) x (80-85%)(THR)

Therefore, your target heart rate range would be 148-157.25 beats per minute

The point of the intensity is that you cannot maintain the pace for long so you work maximally, rest and repeat.  Think of a 100m sprint.  Explosive power & a short, 10 second effort, give or take.


For a longer duration & more endurance focussed training session the intensity would be nearer the 50-65% range.  This is a great way to train too if that is what you enjoy but, even though working at a lower intensity utilises fat well as a fuel source, it will obviously take much longer to burn as many calories overall than a good HIIT session.

























At first glance the above table makes both types of training appear similarly beneficial however, if there is one thing we want to avoid it is potential muscle loss. According to a research article carried out at the University of New Mexico1, HIIT training performed 3 times a week showed a 10% increase in 1 heart stroke volume compared to a long, slow distance training group. In addition, VO2 Max (the body’s ability to use maximal oxygen for energy production) improvements were noticeably higher in an 8 week HIIT training program (15%) vs continuous aerobic training (9%).

Consistent HIIT training has also been shown to improve the efficiency of the body to utilize fat for fuel thus saving carbohydrates and enabling the athlete to train harder for longer.


CyclingSo how is it best to introduce some HIIT training into your schedule? If you enjoy distance running or riding, adding a couple of HIIT sessions into your week could see you significantly improving your power output, i.e. your ability to power uphill more quickly or find that final push to beat your competitor and reach the finish first. It can be the perfect, time efficient side dish to your resistance training main course too if you are looking to maintain muscle whilst shredding fat.


Keep it simple and begin gradually. The beauty of this training is that it can be done in any number of ways be it on a treadmill, running outside, on a bike, a rower or doing burpees (yeah, as if). Fire up your imagination and keep mixing it up. A simple initial workout could be:

10 minute warmup (really, really important so that you don’t injure yourself)

30/60 split x 6 = 30 seconds all out effort followed by 60 second recovery to be repeated 6 times

As you progress, change one variable at a time, e.g. reduce the rest periods down to 45 or 30 seconds, or increase the work effort to 45 or 60 seconds or increase the number of intervals to 8 but probably never more than 10. If you have enough left in the tank after 10 intervals then the intensity wasn’t high enough. Go back and start again!



To notice speedy improvements twice a week is a great starting point building up to no more than 3 times a week. Recovery between sessions is really vital especially given the intensity. Once you have been doing these a while, you can try jogging the recovery periods rather than being bent double wheezing into a bucket. I’m not asking you to enjoy them but I can promise you there is a huge sense of satisfaction at the end plus the wonderful added double bonus of adrenalin and feel good endorphins racing around your body. Not to mention the nerdy science physiological benefits too.

Do you already do HIIT training and, if so, how, how often and have you noticed improvements?

We’d love to hear from you so please post your comments and, if you enjoyed this article and found it useful, don’t be afraid to share it around social media Thumbs up


[1] https://www.unm.edu/~lkravitz/Article%20folder/HIITvsCardio.html
Photo credits : Terry George, Edson Hong, Geralt, Vargazs, Skeeze

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  1. Mike Pollard

    Hi Sophie – this is Mike from your old pump and lift class in Wareham. Hope everything is going great with you? We’ve just lost our only evening HIT session – Insanity – but do you think the other classes, like circuits and pump, can act in the same way as HIT if you really push yourself? My reason for asking is, being tall and slim, I want to gain muscle not lose it, and I don’t have much fat to burn. I feel pretty fit, endurance-wise.

    I’ve been adding a 10 minute row with Jen at the end of one of my pump sessions, and that makes me feel great afterwards. I guess that’s the endorphins. Interesting side effect from all the exercise – I’m feeling less like alcohol and when I do drink it, it makes me feel worse. Oh well, I guess you can’t have everything!

    1. Sophie Russell (Post author)

      Hi Mike, great to hear from you but I’m so sorry that some of the classes have gone. As far as retaining muscle is concerned, Pump is your best bet or a weighted circuit. Pump is designed as a high intensity, high rep class, i.e. one that will build and maintain muscle but also shed fat because your heart rate is elevated throughout (or should be if you use challenging weights). I would probably suggest in your case (if you have time) to add a heavy weight circuit to your weekly routine. You would be aiming to squat, bench press, row and shoulder press heavy enough load to be able to perform only 4-6 reps x 4-5 sets. Build the load gradually and start with a light warm up set. I will post a routine soon that you can use and will explain in more detail.

      Your comments about alcohol are interesting. Certainly drinking alcohol after exercising isn’t a great idea as it will impede your body’s ability to repair and grow muscle. It is probably best served on its own! You may find that your body metabolises alcohol much more quickly being lean and fit which might be why you are left feeling less than great.

      I hope that goes some way to answering your queries. Please feel free to ask away! Go well, Mike and keep up all the great work! cheers, Sophie

  2. Mike Pollard

    Thanks for the advice Sophie and happy new year! I’ve started using a gym routine of heavier weights with fewer reps, but I haven’t been often enough for it to have much effect yet. As I’m doing 4 exercise classes a week, plus weekly badminton and often another racquet sport, it’s difficult to fit in more stuff. I can feel some pretty good muscle just beneath the surface, especially on my legs and abs, but you can’t actually see a six pack and of course there isn’t much bulk.

    BTW, one problem I’ve always had with heavier loads is straining muscles, especially my back. Often I’m not even aware I’ve pulled anything at the time, but the next day…..ouch! I think I know enough by now to warm up properly and maintain good posture, so it makes me wonder whether my physique is unsuited to heavy weights and bulking up (but good at endurance). I think you’re right about the alcohol, but cheers anyway! All the best, Mike

    1. Sophie Russell (Post author)

      Happy New Year, Mike! Great to hear from you. You are clearly very cardiovascularly fit – you do a lot of CV sport. What exercise classes are you doing each week? The point I’m getting to is this – decide what you wish to train for. If it is to have great cardio fitness, then keep doing what you are doing. However, if you really are keen to put on some muscle then you need to focus on that. Doing the odd Pump class plus maybe a few heavier weights sessions in the gym won’t cut it really. Brutal but honest! If you want to run a marathon then train specifically for that however, don’t expect to build muscle at the same time. As great as it is to do lots of different types of exercise to add variety and be generally fit, if you are after a certain goal then you need to look at what you are currently doing and adjust accordingly. I can help with that if you want.

      If you have been doing Pump regularly then I would suggest swapping one or two of your more cardio focussed weekly workouts for 2 or 3 hypertrophy ones, i.e. specifically muscle-building – go heavy! I appreciate your concerns regarding your back – do you do any specific core/Pilates work? Depending on our genetics and our natural body shape (i.e. as it is at its “set point” & not from over/under-eating and therefore manipulating our natural shape), the exercise we do is very often driven by this factor. You are tall and lean and so have the build of an endurance athlete as opposed to someone shorter, more muscular and therefore perhaps with more power and speed. It makes sense that you are good at and enjoy endurance sports. This doesn’t mean to say you can’t put on more muscle but, because of your build, it would be harder. That is simple genetics for you. You can however, still put on muscle. You just need to be more strategic about it.

      So, to go back to my earlier point – if building muscle is really what you want to achieve, then focus on it properly for a few months and then see. Let me know what you are currently doing in a week and I will give you some suggestions. As far as you back is concerned – try to add in some regular, specific core work, be vigilant about technique in all exercises before adding additional load and work on strengthening your gluts. I’m all about the gluts!!

      I hope that makes sense? Go well, train hard, have fun! Cheers, Sophie

  3. Mike Pollard

    Thanks again, Sophie, that all sounds like excellent and professional advice. My current weekly schedule is 2 x pump & lift, 1 x circuits, 1 x stability, core & abs, 1 x badminton (2 hrs), 1 x table tennis (1 hr) and at least 1 x another activity, which could be gym weights or tennis.

    Ever since I heard about pilates and the core, I’ve tried to incorporate that before, during and after my activities, and my lower back has definitely improved a lot. I’m more likely nowadays to strain a random muscle or joint elsewhere if I over-do things.

    Although I would love to put on more muscle bulk, I think you’ve hit the nail on the head when you ask what I enjoy and what my aims are. I wouldn’t like to give up any of those classes and I need the cardio to be effective at my racquet sports. One aim for this summer is to do my first (and maybe my only) sprint triathlon, and I realise that’s not compatible with building muscle and reducing cardio! Maybe after that I’ll get back to you about more hypertrophy.

    A physiotherapist once told me that my gluts were pathetic, which surprised me considering all the sports I’ve done over the years. But they’ve definitely improved a lot since pump & lift, thanks to the squats & lunges – clenching on the way up, of course!

    1. Sophie Russell (Post author)

      Hi Mike, really interesting comments – thanks for filling me in with what you are doing. I love your mix of exercise – you have all the requisite elements for all round strength, fitness & agility, i.e. you are ticking all the boxes and it is clearly varied enough that you enjoy the lot. Music to my ears!! I am especially pleased to hear that you are incorporating some Pilates into your schedule & that is is helping your back. For all the high octane running, jumping and heavy lifting we do, it is important to balance that with some low intensity, gentle, focussed work to even out any imbalances and also strengthen the intrinsic, smaller support muscles that often take too much of the load if the big, shouty muscles (biceps, gluts, pecs, quads, etc) are weak, fatigued or firing incorrectly.

      I think the goal of a sprint triathlon is a fantastic one – I would suggest working towards that and then maybe changing direction afterwards towards hypertrophy. Working on your splits will be the key.

      Now onto the no-small matter of your gluts! I’m all about the gluts, me! This is something I encounter every day through my work – ineffective gluts or poor glut activation regardless of fitness, strength etc. Physios often say they’d be out of a job if people’s gluts actually worked, it’s that common that they don’t! Weak gluts lead to back & knee issues amongst others. I used to bang on about it all the time in Pump & Lift – gluts & abs need to work together to support the position of the pelvis & therefore the alignment of the lower back. If, for example, you do heaps of crunches but your gluts are lazy you’ll end up with an imbalance & your lower back will take over the slack & become over-worked or worse. The problem is that if the muscles are firing incorrectly or are lazy – once that pattern has begun it takes a lot of work to reverse it as the body will automatically take the path of least resistance. Squats (wide stance preferably) & lunges are great exercises. In addition you can also do single leg deadlifts – I love this exercise because, if done properly, you know very quickly where your gluts are!! Will post a clip of the exercise so you know what to do.

      I hope that helps a bit. Keep up the strength work you are currently doing if possible because it will only complement your sports. Then down the line you can think about switching things up a bit.

      Let me know if you have any more queries. Go well.


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