Cardio can be a bore. One of my favourite things to do is go for a run around the park on a fresh Sunday morning. There’s nothing better to wake you up and get the blood pumping and kick start your metabolism (or work off a hangover!). But often the reality of trying to fit in 3 cardio sessions a week means resorting to the pretty boring grind of the treadmill or cross trainer on a weekday night after work.

But it doesn’t have to be that way! I used HIIT to get really lean, with my workouts taking up as little of my time as possible.

What is HIIT?

High Intensity Interval Training or HIIT is all about doing short bursts of exercise at around your maximum effort level (basically as fast as you can) and then alternating it with a similar length burst at around 60% of that effort level. So on the treadmill you might do 1 minute at a sprint, followed by 1 minute at an easy jog whilst you get your breath back. This means you’re doing cardio at a high intensity rather than for a long slow grind, getting your heart rate higher and using up more calories – it’s basically a bit like Japanese Tabata training but in an extended form.


Tabata consists of performing an activity all-out for 20 seconds, resting for 10 seconds, and then repeating the on-off sequence for four minutes total.

So what are the benefits?

  1. HIIT increases your metabolic rate, helping your body to burn fat even after you left the gym.
  2. Saves you loads of time spent on the treadmill, making it easy to fit around your schedule.
  3. You can do it without any equipment (try sprinting around the park for 1 minute followed by a 1 minute jog, or running up a hill).
  4. HIIT has been shown to have various health benefits such as improving your overall fitness, blood pressure and cardiovascular health.
  5. It can help to burn abdominal fat whilst also maintaining muscle mass (woohoo!)

A bit of the science

For years we’ve been told that the best way to burn fat was to slog away for hours in the gym, keeping your heart rate within the optimum ‘fat burning zone’, which is typically between 55% and 65% of your maximum heart rate (the basic calculation of which = 220 – your age). The premise behind this theory was that at lower heart rates, your body is using energy taken from your fat stores, as opposed to glycogen stores, so you will be burning fat rather than muscle. However this rule misses one important point; the absolute amount of calories burned is also critical. A more intense workout – which increases your heart rate to the higher ‘cardio’ or ‘peak’ zones – will result in more absolute calories being burned, and often in a shorter amount of time.

Workouts to Try

I’ve used HIIT loads as part of my own training and it’s really my main form of cardio. I’ll try and fit in 2 or 3 15-20 minute sessions after workouts during the week, depending on whether I’m looking to tone up or gain size. Then I might do 1 longer jog at the weekend for say 25 minutes.

If you haven’t done HIIT before then you should take it easy at first and then keep increasing the speed as your body gets conditioned to it. I also wouldn’t recommend doing a HIIT session either the day before or immediately after a heavy legs session!

Workout 1 – Treadmill

Rest speed: 8km/h (9km/h for me)
Sprint speed: 15 km/h (17.5 km/h for me)

Warm-up – 2min @ rest
Interval 1 – 1min sprint
Interval 2 – 1 min rest

Repeat intervals 1 + 2 for 8 times (i.e. 16 minutes). Over time you should try and build this up to repeating 10 times (i.e. 20 minutes total).

Workout 2 – Rowing

Rest speed: try a leisurely, slow row
Sprint speed: as fast as you can

Warm-up – 2min @ rest
Interval 1 – 1min sprint
Interval 2 – 1 min rest

Repeat intervals 1 + 2 for 10 times (i.e. 20 minutes).

My top tips

  • Ease yourself in slowly. Don’t stick the treadmill on 20km/h on day 1! Build up slow but make sure you push yourself a bit more each time.
  • Alternate with other forms of exercise. Mix it up – you don’t necessarily want to do HIIT for every cardio session as it can put extra strain on your body. Give yourself some time to recover every now and then.
  • Get some good trainers. When you’re sprinting (or running fast!) the last thing you want is footwear which isn’t properly suited to your gait.
  • Choose an exercise you enjoy. Not everyone loves running! Rowing can also be a great alternative or the bike.

Try a class

If you live in London like me then there are load of studios popping up all over the place offering pay-as-you-go HIIT-style workouts. Here are a few of the most well known ones.

Project Fit

Project Fit

Project Fit – This City-based studio focuses on HIIT classes, either 35 minute or 1-hour duration. Each class is an intense combination of work on the treadmill (often involving hill / interval sprints) and floor work using hand-weights, steps, BOSU balls or TRX straps. Every class is different, and new additions involve specific ‘Run’ and ‘Core’ classes, which focus on one or the other.

HIIT GYM – With 2 London-based studios – in Richmond and West Hampstead – HIIT GYM classes are 45 minutes long, incorporating time on treadmills, rowing machines, SkiErgs as well as TRX straps and free weights. After your workout you’ll receive a personalised email charting your progress.

Rebel 1 Studio


1Rebel – A new addition to the London fitness scene, 1Rebel has recently opened a City-based studio, with another in the pipeline. 1Rebel offers high intense fitness sessions against a backdrop of live entertainment. There are two types of classes, both 45-minute duration: ‘Ride’ is a group cycling class incorporating weights and bands. ‘Reshape’ is a group class involving WoodWay treadmills and patented workout platforms. Lunchtime sessions include a complimentary lunch or juice from the onsite Roots & Bulbs juice bar.

Barry’s Bootcamp

Barry’s Bootcamp – Probably one of the better-known HIIT workouts on offer, Barry’s has a studio in Euston, with another City-based studio due to open in early 2015. The signature 60-minute workout combines a 25-30 minute interval cardio routine with 25-30 minutes of strength training. Trainers, muscle groups and workout vary throughout the week so no class is ever the same.

HIIT Studios – From a Southwark-based studio, HIIT Studios offers over 200 classes a week, from 20 minute HIIT sessions to 30-minute classes focused on boxing, kettlebells, TRX, pads or sparring, all based on the HIIT philosophy. 60 minute Jiu Jitsu, Muay Thai Kickboxing and yoga classes are also on offer.