Staying fit and healthy

Is HIIT worth the hype? We’ve devised an at-a-glance, comprehensive guide to high intensity training that gives you the low-down on the current fitness trend.

The lowdown on HIIT

High intensity interval training (HIIT) is any exercise session where you’re alternating between tough, high intensity intervals of a fixed time with set rest periods. For example, you might do three rounds that include five 40 second exercises, with 20 seconds rest inbetween.

Intervals are usually performed at around 80% to 95% of your MHR (Maximum Heart Rate – the maximum number of times your heart beats in a minute). Recovery times vary and are usually taken at around 40-50% MHR. Sessions typically last between 4-30 minutes.

What are the benefits of HIIT?

The ACSM states that HIIT can improve cardiovascular fitness, blood pressure, insulin sensitivity and abdominal fat levels. Various studies have confirmed the positive effect HIIT has on fitness levels – great news if you’re time poor or struggle to find the motivation for longer workouts.

What’s on offer

The big gym chains all offer HIIT classes, most of whom offer sessions of varying lengths and styles. The Gym Group, Virgin Active, PureGym, David Lloyd and Fitness First offer classes that cater for every HIIT appetite while sport and leisure facility operators Better and Fusion Lifestyle also provide a good choice of HIIT routines in many of the leisure centres they operate.

There are a number of high intensity workout ‘brands’ offering sessions and communities in clubs and/or on the internet including CrossFit, Tabata and the ever popular Insanity.

Good, easy-to-follow high intensity routines are in abundance on the internet. Google ‘HIIT home’ and you can’t go far wrong.


So are there any downsides to high intensity training?

The higher rate of injury.

If you switch from couch potato mode to 15 minutes a day of box jumps and burpees you’re asking for trouble. Many HIIT routines include high impact body weight moves – the type of dynamic, often explosive exercise required to raise your heart rate sufficiently in a HIIT routine. Start slow, don’t be afraid to sit out certain moves and remember – HIIT can happen anywhere. Cranking up the intensity on the cross trainer might be a safer way to get started.

Weights in the gym

It might not benefit your waistline as much as you’ve been led to believe

While the EPOC (excess post-exercise oxygen consumption) or ‘afterburn’ effect of high intensity training is not to be overlooked, beware the claims you’ll burn hundreds of calories in such a short space of time. You can only burn so many calories in fifteen minutes and, as unpopular as this bit of science currently remains, calories count.

It can be difficult to sustain

HIIT can be fairly difficult to sustain for those who struggle with motivation. Once the novelty of that initial post-workout nausea has worn off, trying to stick to a fitness diet consisting solely of higher intensity workouts may prove unappealing for some in the long term, however plausible the push from high profile fitness enthusiasts.

Is HIIT for everyone?

The ACSM advise that those who have been inactive or sedentary for prolonged periods of time may be more vulnerable to the coronary disease risk with high intensity exercise, and this risk increases if any of the following are applicable: a family history of heart disease, diabetes, high blood pressure, abnormal cholesterol levels, obesity or smoking. If in doubt, there’s no harm in getting the all-clear from your GP or consultant prior to going for the burn.

Tips for getting started

It’s a good idea to have a good foundation or base level of fitness before you start. Regular sessions of moderate-paced activity a few times a week (could be walking or anything that raises your heart rate) as well as some muscle-strengthening exercises is wise before starting some of the more high impact regimes (see below).

Mix up your HIIT sessions. Most spinning and circuit classes use interval-style formats and you can do these under the eye of a qualified instructor. And low impact cardio machines such as the rower, bike and cross trainer are all good for maintaining intensity minus impact.

Staying injury-free

  • Strengthening your muscles with body weight moves such as lunges, squats, press ups and planks before you engage in some of the higher impact body weight exercises often favoured by HIIT routines may help to prevent injury. Burpees, and all their variations; box jumps, jump squats should ideally all be performed on relatively well conditioned muscles.
  • Don’t overdo the frequency. Three HIIT sessions a week should suffice, fewer if you’re starting out. Signs that you may be overdoing the tough stuff include fitness and training plateaus, feeling more tired than usual and more frequent illness.
  • Mix with easier workouts. Don’t neglect lower intensity workouts. You may be surprised to hear the two types of workouts tick different boxes. Low intensity exercise sessions are a great way to build a good aerobic base and burn calories without burning out.