The phrase ‘HIIT’ has been around in the fitness industry for a while now. The fitness industry is one where fads and trends come and go but it seems like HIIT is here to stay! Let’s be honest HIIT has been around a long time….think back to what I’d call ‘old school circuit training’ done in the large sports hall at your local leisure centre, that was HIIT training! As a Personal Trainer, I often hear my friends and clients talking about how much HIIT training they are doing, but are feeling frustrated that they are not seeing the results. Often it’s simply because they aren’t working at the right intensity to reap the rewards of HIIT training, so I thought I’d write this guide to HIIT training and also look at the benefits of HIIT training.

What Is HIIT Training?

HIIT stands for High Intensity Interval Training, which is a form of cardiovascular training. During HIIT training you alternate high intense bursts of exercise with easier intervals, for example you may sprint as fast as you can for 45 seconds, then walk for 2 minutes and repeat this 8 times. Or you might do a circuit of cardiovascular based exercises such as star jumps, burpees, dynamic lunges, etc performing each exercise for 30 seconds with 30 seconds rest between. There are so many different ways you can incorporate HIIT training into your workouts but to really see the benefits you need to focus on two key points:

  1.  The intensity of your workouts. The clue is in the title ‘high intensity interval training, to really take advantage of the benefits of HIIT training you need to be working at a hard enough intensity. One of the biggest reasons people do not see results from HIIT training is simply because they ‘coast’ during their workouts and do not push themselves hard enough during the ‘work’ intervals. Now, it’s fair to say here that this is very individual…..what be high intensity for one person may be an easier intensity for another, and vice versa so it’s important not to compare yourself to anyone else when doing HIIT training and work at your own intensity but do make sure you push yourself hard enough. See below for how hard you should be working. 
  2. Keep the majority of your exercises cardiovascular based, this will keep the intensity high. Yes, to a degree strength based exercises such as press-ups, squats, etc will keep your heart rate up, especially if you format your workouts correctly, but you need to ask yourself…..are these exercises making me work at a high intensity? If not, ditch them and add exercises which will.

What Intensity Should I Be Working At For HIIT Training To Be Beneficial?

Ideally when you’re performing interval training, you should be getting into your anaerobic training zone during the ‘work’ intervals, i.e you can’t talk very much and you’re becoming very breathless. Anaerobic basically means ‘without oxygen’ so it’s an intensity which you can’t perform for very long before needing to recover so you can replenish your oxygen stores again.

We tend to use two ways of measuring intensity….heart rate zones or RPE (Rate of Perceived Exertion). If you’re monitoring your intensity using a heart rate monitor then, depending on your fitness levels, your anaerobic zone will be around 80-100% of your maximum heart rate. If you’re using a scale of 1-10 (with one being the easiest) for RPE, then you want to be a good 8+ on this scale. A good rule, is if you can talk for more than a few sentences during the work phase you’re not working hard enough!

With regards to length of the intervals, again this will vary from person to person depending on their fitness levels and experience of HIIT training. If you’re new to HIIT then start with shorter intervals and longer or equal recovery, perhaps 30 seconds work / 30 seconds rest. Then as you become fitter either decrease the recovery time or increase the work time….or both!

What Are The Benefits of HIIT Training?

  1. Good For Fat Burning – Research suggests that HIIT training burns more calories than steady state training, which helps with a greater calorie deficit if you’re looking to burn body fat and lose pounds. Go for a 30 minute steady-state run or so a running HIIT session instead and the likelihood is that you’ll burn more calories in the HIIT session.
  2. Higher Increase In Metabolism Post Workout – In addition to burning more calories, it’s also thought that HIIT training keeps your metabolism elevated for longer after a workout than if you do a steady state session. This is called your ‘EPOC’ or ‘Exercise Post Oxygen Consumption.  In fact, some studies show an increase in metabolism for up to 24 hours after a HIIT workout.
  3. Great For Improving Your Cardiovascular Fitness Levels –  When you perform HIIT training you are putting your heart under a great amount of stress. Your heart is a muscle, and just like any other muscle, the muscle responds to this stress by becoming stronger overtime and this results in improved cardiovascular fitness. In the future workouts which seemed hard will now seem easier, or you’ll find you can push yourself more due to your higher levels of fitness.
  4. Can Do Anywhere & Without Equipment  –  As I suggested earlier in this blog, the majority of your exercises should be cardiovascular based and so many of these can be done without using any kit. We’re talking exercises such as mountain climbers, squat jumps, star jumps, high knees, skater jumps, power lunges, burpees (sorry!!!), toe taps….the list goes on.

Whilst HIIT training is a great mode of training, if you’re new to exercise or suffer from any medical conditions then we would recommend speaking to your GP or a fitness professional before you undertake any HIIT training.