the joy of strength training


July 14th, 2012 at 12:51 pm

Interval training for fitness and fat loss

Interval training on a rowing machineThis post was inspired by a friend of mine who wanted to know what he could usefully do on a crosstrainer apart from watching the news on its screen.

Interval training is the best way to use any cardio machine, whether it’s a treadmill, a crosstrainer or a rower, for improving fitness and losing fat.

You can also do interval training the traditional way, by running or cycling outdoors.

For fitness and fat loss, interval training is better than just steady state cardio, i.e. going for a run.

All you need to know to get started are a few simple principles and you have a lifetime’s worth of training sessions at your finger tips.

What is interval training?

Interval training is where you go as hard as you can for a given period of time, say, 30 seconds (the ‘work’ interval), and then go very easy to recover (the ‘rest’ interval).

The principle behind interval training is that by working at a high intensity for short bursts, you keep your heart rate higher than steady pace cardio, raise metabolism and burn more calories.

You also get much more post-exercise calorie burn than you do from steady cardio – your body continues to break down fat stores for up to 36 hours after intense exercise in order to recover.

So if you are wanting better fitness or more fat loss, or a combination of both, interval training will help you reach your goal – along with resistance training, of course, but that’s another post!

How is it done?

The key variable to manipulate is the work:rest ratio. For example:

1:1 – e.g. 2 mins work, 2 mins rest

1:2 – e.g. 1 mins work, 2 mins rest

1:3 – e.g. 30 secs work, 90 secs rest

If you rotated through these ratios, you would work all your energy systems (aerobic, anaerobic etc).

It’s important to note that you go as hard as you can during the work interval, so a 30 sec interval should be faster than a 2 min interval because you are going all out for only 30 secs.

The recovery period should be very easy, not just slightly less fast. We’re talking a very slow trot or even a walk. It is important to recover properly so that you can give it everything in the next interval, where the real work gets done.

The way to organise your interval training session is as follows:

  • Warm up for 5-10 mins starting easy and getting progressively harder until your heart rate is moderately high (on a scale of 1-10, around 7).
  • Perform 5-10 intervals at your chosen work:rest ratio, for example:  1 min work/2 mins rest x 6
  • Cool down for 5 mins, starting reasonably hard and getting easier so that you bring your heart rate down in a controlled manner.

An interval session can be a standalone session or can be done after a resistance workout.

Choosing the right variables

As for how many intervals to do, start low at around 4-5 and increase every session or every week until you are up to around 10.

The shorter the intervals, the more you can fit into a session. Aim for around 20 mins of intervals to start with.

For example, if you chose to do 2 min/2min, that is a total of 4 mins per interval set. If you did that 5 times, the total work time would be 20 mins.

If you were doing 30 secs/90 secs, that is a total of 2 mins per interval set. So in 20 mins you could get twice as many intervals done. Due to the higher intensity and greater number of intervals, this session would be more demanding than a 2 min/2 min session.

I recommend starting with work intervals of 1-2 mins. As you get fitter you can try work intervals of 45 secs and then 30 secs.

The most demanding type of session is something like 30 secs/30 secs. Very short work period and very short rest period. It takes experience to be able to perform this effectively, i.e. to really push yourself hard for 30 secs, and then recover sufficiently to be able to perform the next interval at a high intensity. If you can do 10 of these, you’re hardcore!

My tip for short intervals of 30 secs or less is to avoid using a treadmill as it takes several seconds to speed up/slow down.

Better machines are the rower or the bike. If you want to run, simply run outside.


Make sure you progress over time by gradually increasing the speeds/levels at which you can perform each interval.

Progression is the key to results. Your body adapts to the stress you put on it, so you need to gradually increase the stressor to force the body to keep adapting – i.e. getting fitter and burning calories.

It’s a good idea to put a programme together for yourself, rather than waiting until you get to the gym to decide what to do. Sticking to a planned programme should yield better results.

Let’s say you go to the gym 3 times a week. You could do a different work:rest interval each day, for exmaple:

Monday: 2 min on/2 min off x 4

Wednesday: 1 min on/2 min off x 6

Friday: 30 secs on/90 secs off x 8

Then the following week you could either increase the number of intervals or keep the number of intervals the same but increase the speed/level at which you perform each one. Increase only one variable at a time.

My suggestion is to take a 3-4 week period (a training cycle) and pick one variable to change. For example, the number of intervals.

Using the example above, your training cycle might look like this:

Week 1 Monday – 4 intervals

Week 2 Monday – 5 intervals

Week 3 Monday – 6 intervals

When you had completed that cycle, you could then pick another variable for the next training cycle, such as speed. In that scenario, you would keep the number of intervals the same, but increase the speed/level  each week. For example:

Week 1 Monday – 4 intervals @ 11 kph

Week 2 Monday – 4 intervals @ 11.5 kph

Week 3 Monday – 4 intervals @ 12 kph

Why not try putting together your own 12-week programme, using these principles? It doesn’t have to be perfect; you might find once you start doing it that you’ve been over-ambitious or under-ambitious – if so, tweak it. Following a programme is the best way to make progress.

There are so many ways to do interval training. What I’ve suggested here is a starting point, but there are many paths you can take to continue. Good luck!

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  • 1

    Thank you for this page good info xxx

    nichola wild on February 10th, 2013
  • 2

    A variation on this that I’ve heard of is to do 8/12 on a cross trainer machine, for example. This is actually a ratio of 1 to 1.5 (or 2 to 3) work to rest ratio.

    Each sprint lasts 8 seconds followed by 12 seconds of rest at a much lower rate, for work intervals of 20 seconds. Hence there are three short sprints per minute. I’ve done this for up to 20 minutes (I refuse to do more than that!) and it’s a great workout for losing fat. Tough as all Hell though, especially towards the end.

    Mark on April 15th, 2013


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