Cardio — When, why, how

People often get confused with cardio and its understandable why. The internet gives us instant information at the click of a button and to the average gym goer, its hard to pull apart what is real and what is made up.

Really all health and fitness is, is a mixture of opinions of professionals arguing who is right and who is wrong. Their way not your way kind of malarkey. All that means to us is that one coach or professional found one particular route effective and the other found another route effective, or they had a bad experience or in-effective experience with one and no longer believe it to be beneficial for anybody else and not just themselves. What we cannot deny though are studies, because if science states something is fact, it’s pretty much fact.

So here is my opinion, my two pence on the matter and what I believe to be effective after not only taking things away from studies and seminars, but trailing it on myself in physique competitions and on numerous, numerous clients I have helped compete in competitions or lose weight/fat.

First we must actually consider why it is we are doing cardio. If the goal is fat loss, perfect, we are looking to create further expenditure and increase output. If your goal is muscle growth, is cardio really beneficial when you will be burning calories you could be keeping to guarantee you remain in kcal surplus. After all, a calorie surplus is what causes us to grow. If cardio was to be added during this phase, its type should be low intensity and its duration should be limited. I would only consider cardio off season for heart health and general well being, other than that rest up, eat as much as you can and recover the best you can. For the sake of it, I will mention I have used HIIT in the past with clients who struggled with their appetite. All I would do is pull back a few kcals from carbohydrates and then add in two HIIT workouts in the form of resisted bike sprints to help pic up metabolism, then remove after ten to fourteen days and slowly increase kcals.

If fat loss is the goal we need to consider a few things;

  • Training History (experience levels)
  • Time restrictions (work commitments, responsibilities)
  • Current condition, fitness and health levels (fit, fat, what?)
  • Time we have to achieve goal

This is important because if you, or the client has had months, even years away from exercise, putting them straight into HIIT (High Intensity Interval Training) may not be as beneficial as you think. It could cause too much stress and loss of energy taking away from their workouts and day to day activities which can even result in demotivation. I’ve even seen clients feel nauseas and lose appetite, so start small and build up gradually as fitness levels improve and weight/fat decreases.

Let’s look at our options;

LISS: Low Intensity Steady State

Ie; 30 minutes power walk or 20 minutes on a cross trainer

This type of cardio is the more popular type. It’s favoured because it requires less effort, all you have to do is maintain a consistent pace for a longer period of time. I favour this personally because I prefer a male or female client to be able to perform at their best during their weighted sessions, so the less expenditure they spend elsewhere, the better for me. Cardio to me aids fat loss, it’s another tool we utilise but it is our weight sessions and performance that dictates body composition changes and results. I personally look to utilise LISS 2–3 times per week when starting out. Actually I lie, I generally start out a client with zero cardio to see how effective nutrition alone is, THEN when I look to introduce CV, I start at 2–3 LISS sessions per week, ideally fasted or separate from their workout.

Although steady state doesn’t have a direct correlation with your metabolic expenditure it does however increase output during the period of time its being performed which means we can keep input that much higher overall.

Starting from 20 minutes building up to anything as high as 90 minutes per day (note; if nutrition is on point, it’s common clients max out at 45 minutes and if 90 minutes was needed it would be split not done in one sitting).

Here is how I may look to progress a clients expenditure over the weeks;

Week1; 3 x 25 minute sessions
Week3; 5 x 25 minute sessions 
Week6; 5 x 40 minute sessions 
Week 10; 7 x 45 minute sessions

HIIT: High Intensity Interval Training

IMO is very useful, but it must be limited. HIIT is very demanding and can tax our CNS (central nervous system) a lot, meaning you, the client can and will feel very fatigued and drained. Kind of like a low rep high load strength session, you know where you don’t feel the pump is great but you’re dying. I will always limit proper HIIT to three times per week max, especially for competitors and I will generally remove it four weeks out and make all sessions low intensity as its too demanding, and at this stage kcals and overall expenditure won’t be able to warrant it. If you or the client has also plateaued, HIIT maybe a short term useful tool to help them progress again as well so use it wisely.

If they’re progressing, weight is coming down and body composition is changing then HIIT may not even be necessary. If it was to be introduced, wait till the clients energy and recovery levels have improved. Start off at just two sessions per week, maybe on rest days and look to do it between meals opposed to fasted. Get some food in you so you have more to give and can really exert yourself.

Remember HIIT isn’t 30:30 ratio (30 seconds sprint, 30 seconds rest) this is more so MIIT (Medium Intensity Interval Training). If you can exert yourself hard for 30 seconds, exert yourself even harder for 13–20 seconds and then you are most likely performing HIIT or as close to it as you can. Here is how I would set up a client for their first HIIT session;

5 minutes steady state warm up using the equipment they will use to sprint

15sec max effort sprint with slight resistance / 40sec recovery x 6

10 minutes steady state cool down period on treadmill to prevent blood pooling allowing it to circulate and slowly reduce heart rate before stretching out.

Some clients may also perform rounds of HIIT in weighted exercises such as battle ropes, prowlers etc and although it maybe HIIT, I would put this in with strength and conditioning work.

Strength & Conditioning

Admittedly this isn’t something I do, or get my clients to do so often. I’m more of a LISS in a morning, weights in an evening and HIIT when we need to kinda guy. However, personal trainers who work with clients on a face to face basis I believe strength and conditioning workouts to be a great way of achieving both fat loss and muscle stimulus. These kind of workouts create huge amounts of expenditure and also improves the clients strength, fitness and recovery levels. These workouts may consist of things like weighted prowler sprints, sledded rope pulls, farmers walks etc… more athletic style of training but fun for the day to day client as well.

Putting it all together…


You know LISS is effective and why. But HITT is also very effective, so you’re kind of none the wiser. Here is how I would introduce all of the above.

First of all get your nutritional habits in check. Be consistent with this for 10–14 day before looking to introduce cardio and see the effects and results from this alone. Then look to introduce a few low intensity sessions till your recovery and fitness levels improve. Before reducing foods, look to increase expenditure so maybe add to the sessions or duration. Then add HIIT to the mix…

3 x 25 minute LISS (Fasted on training days) 
2 x HIIT (Rest Day CV)

Again, look to add to the LISS and as intake gets lower, look to replace the HIIT sessions with more LISS so you don’t cause yourself to fatigue and plateau.

All in all cardio is a very effective tool to aid fat loss and should be utilised but never as a primary tool. Prioritise weights and nutrition and use cardio as something to increase output and create that bigger calorie deficit.