Over the last 5 years or so, there’s been a definite movement away from traditional cardio in the personal training community. As a result, like almost everything health and fitness related, there’s divided opinion on whether it’s any good or just elevates your cortisol levels, causes Alzheimer’s and then kills you.

So what’s the truth?

Well, it depends.

In order to assess cardio’s effectiveness, you need to first determine what ‘cardio’ is and then determine the objective of doing it. To make this simpler, I’ve compiled a list of what I consider to be the main forms of exercise considered as cardio and another list of the main reasons for doing them.

Types of ‘cardio’

Machine based steady state – treadmills, cross trainers, etc.

Machine based interval training – as above

Free steady state – Running on a track, outdoors, cycling, etc.

Free Intervals – As above

Rhythmic Group Exercise – Aerobics, Body Attack, Leg, Butts and Tums, etc.

Circuit training – A sequence of exercises performed with little or no rest in between

Energy Systems Training – A sequence of exercises with diminishing absolute strength demands

Metabolic Training – A sequence of exercises designed to maximise calorific expenditure

Objectives of Cardio

Improve cardiovascular fitness

Improve body composition

Improve athletic conditioning

Improve lactic acid tolerance

Get moving

Feel like you’re doing something while disengaging mentally

Now most people, particularly trainers, will have gone through the first list and nodded away to most of what’s on there. The second list however, is normally fine until people reach the last two points. You see as a fitter percentage of the population, it can be easy to forget that for some people, just doing something is waaaaay better than doing nothing. Some people just want/need to get started, others just want something to take their mind off life. So with that in mind, here’s the first list again, but this time with each method is good for and more importantly, any considerations relevant to each benefit. If you’re not the patient type however, there’s a chart at the end with an easy to use cheat sheet. As with all of the following, the opinions are based on the different methods being used at an appropriate intensity. Be aware though, that there may also be considerations outlined in the text that changes a particular methods score.

Machine based steady state

Improve cardiovascular fitness

Yes. Although this tends to be specific to steady state exertion. I.e. you’ll get better at steady state exercise, but the improvement won’t necessarily correspond to your interval based fitness. It also tends to be modality specific. So just getting better at running on a treadmill won’t make you better on the rower.

Improve body composition      

Yes. However, only ever so slightly unless you do tonnes of the stuff.  If you want to get leaner, you need to address your nutrition. There is also a small body of research that indicates the ‘dirty electricity’ from cardio machines may be harmful, however, obesity and heart attacks are worse. Most of the research, both scientific and anecdotal, seems to support this as a means of exercise for carbohydrate depleted individuals or people with appreciable levels of muscle mass. Primarily because if you’ve got no sugar in your blood stream, you’re probably not capable of doing anything much more intense. And if you’ve got a fair level of muscle mass, that’s a lot of tissue burning calories.

Improve athletic conditioning

Ish. In elite endurance athletes, there may be some benefit to training on a rower or turbo trainer, but athletic conditioning involves small muscle groups that simply don’t fire as actively on machines.

Improve lactic acid tolerance  

Yes, but only if the intensity is high enough.

Get moving                                     

Absolutely. For me, this is where machine based steady state training really comes into its own. It has low barriers to entry, requires very little skill and is easy to get started on. If a sedentary individual needs to become more active safely it’s a great place to start. But once adherence is established I’d move to something else.

Feel like you’re doing something while disengaging mentally  

Again, absolutely. One of the most common validations I hear for running on a treadmill, is that it’s better than going to the pub. Now whilst there are better options available, if those two are the only two a person is prepared to consider, then yes, it’s the best option.

Machine based interval training

Improve cardiovascular fitness

Yes. Like the steady state though, machine based intervals also tend to be modality specific. So just getting better at running on a treadmill won’t make you better on the rower. Also has limited carryover to non-machine based activity. I once ran a four minute mile on a treadmill, mainly by bouncing a lot when I ran, therefore letting the belt move under me. The closest I got in real life was a little under 5 minutes. In addition, certain machines don’t have the same muscle recruitment patterns as their real world equivalents.

Improve body composition      

Yes. But again, as with steady state exercise, if you really want to get leaner, you need to address your nutrition. There is also the ‘dirty electricity’ concern. It does however allow you to trigger reasonable levels of EPOC (Excess Post-exercise Oxygen Consumption, i.e. more calorie consumption than normal after you stop exercising).

Improve athletic conditioning

Yes. Although it will be modality specific and again lacks the carryover to it’s real world counterparts.

Improve lactic acid tolerance  

Yes. Only if loading is appropriate though.

Get moving                                     

Absolutely. Again the low skill requirement and easy access make it a great place to start. But once adherence is established I’d still move to something else.

Feel like you’re doing something while disengaging mentally  

Yes. Particularly for the one button intervals. Just push a button and off you go

Free steady state

Improve cardiovascular fitness

Yes. Although this tends to be specific to steady state exertion. I.e. you’ll get better at steady state exercise, but the improvement won’t necessarily correspond to your interval based fitness, although it will be better than its machine based counterpart. It also tends to be modality specific. So just getting better at running won’t make you a better cyclist.

Improve body composition      

Yes. However, only ever so slightly unless you do tonnes of the stuff.  If you want to get leaner, you need to address your nutrition. There is some research that indicates the micro trauma and wear and tear from high frequency activity can cause repetitive strain injuries and muscle imbalances unless addressed, but again, obesity and heart attacks are worse. Otherwise this is also an ideal means of exercise for carbohydrate depleted individuals. If you’ve got a fair level of muscle mass, it may help but only with lower impact or impact free options, otherwise that mass might work against you.

Improve athletic conditioning

Absolutely. But only as part of an aerobic base conditioning programme specific to a particular sport, i.e. running, cycling, swimming, etc.

Improve lactic acid tolerance  

Yes, but only if the intensity is high enough.

Get moving                                     

Absolutely. Although again, size and mass are considerations. For obese populations I’d always recommend walking, or if size and balance allow, cycling. The risks of anything higher impact outweigh the benefits in my mind.

Feel like you’re doing something while disengaging mentally  

Again, absolutely. One of the most common validations I hear for running or cycling, is that allows people to switch off and forget about jobs, house, spouse, etc.

Free Intervals

Improve cardiovascular fitness

Yes. Much more so than the steady state alternative. Has the advantage of greater levels of muscle recruitment and improved balance and limb control.

Improve body composition      

Yes. But again, as with steady state exercise, if you really want to get leaner, you need to address your nutrition. Like it’s machine based counterpart though, it does trigger reasonable levels of EPOC.

Improve athletic conditioning

Yes. Although it will be modality specific. For me this is where it has the most benefit as a conditioning tool. Intervals for runners and cyclist have been shown to be an incredibly effective means of improving conditioning.

Improve lactic acid tolerance  

Yes.

Get moving                                     

Yes, although for someone unused to exercise this may not be the best place to start. The key would be to keep the overall intensity low but varied.

Feel like you’re doing something while disengaging mentally  

Yes. But less so because of the need to monitor your own progress. Modern timers and phone apps can help with this though.

Rhythmic Group Exercise

Improve cardiovascular fitness

This is a tough one to answer definitively, simply because of the sheer volume and variety of classes available. Body Attack for example has a high calorie demand if done well, but if coasted through, will do very little for your CV fitness. As a general rule of thumb, if you find yourself breathless regularly during the course of a particular class, as a result of the activity involved, you’ll probably get fitter as a result.

Improve body composition, Improve athletic conditioning & Improve lactic acid tolerance

Again, because of the varying demands of different classes, it’s hard to take a single position on the effectiveness of group classes for any of the above. However, if the class is going to do anything for your physique, conditioning or endurance, you should notice it within a couple of months. If you haven’t noticed any improvements in that time, pick something else.

Get moving

This is fairly straightforward. One of the main benefits to group exercise is the social interaction. So if you want to get moving and feel that doing so in the company of like-minded people would make that easier, then this option may be for you. Be aware though, that as discussed above, every class is different and most are instructor dependant. So one boot camp is not necessarily like another, nor is one Spinning or Indoor Cycling class like another.

Feel like you’re doing something while disengaging mentally

For some people, having someone tell them what to do, is just the opportunity they need to switch off mentally. If that’s you, then think carefully about which class you choose. Zumba for example, whilst great fun may be a little too complex for some people. Spinning in comparison is pretty straightforward. The rule of thumb here is to try a number of different types of classes with a number of different instructors until you find one that’s a fit for you.

Circuit training

Improve cardiovascular fitness

It can, but again it can vary drastically depending on the programming skill of the instructor. That said, the thing I like most about circuits, is that what you get out of them is almost a direct reflection of what you put in. So if you’re working hard, then yes, you’ll probably get fitter.

Improve body composition

Like the previous objective, this depends on you and how much effort you put in. If you’re attacking each station with everything you’ve got, you should spike your metabolism nicely. Therefore, over time, you should see some improvements in body composition.

Improve athletic conditioning & Improve lactic acid tolerance

These are dependent on three factors: the programming, duration and the participant. If the circuit is comprised of Bosu squats and Swiss Ball crunches, then it’ll probably do jack for your athletic ability. However, if it focusses on the basics, squats, lunges, etc. then it may help if you’re applying the appropriate effort for a reasonable period of time.

Get moving

I love circuits. They’re what got me my break into the fitness industry over 20 years ago. However. The type of circuit that’s likely to be accessible enough to an overweight beginner, probably won’t do much for everyone else. So if you choose one specifically aimed at people just getting started, then great. Otherwise, you could find yourself overwhelmed and disenchanted before you’ve had a chance to really get started.

Feel like you’re doing something while disengaging mentally

Again, this really depends on the circuit and how it’s run. If you’re changing exercises every 30 seconds, then probably not. If you’re on each station for a minute or more, then maybe. As with some of the other options try a number of different classes with a number of different instructors until you find one that’s a fit for you.

Energy Systems Training

Improve cardiovascular fitness, Improve athletic conditioning, Improve lactic acid tolerance

Absolutely. The high energy demands of EST, coupled with the variability in energy requirements mean your body is subject to a number of challenges in quick succession. As a result, the body adapts quicker and you become fitter.

Improve body composition

The theory of EPOC is the main swaying factor here. If your metabolism stays elevated for a period where energy demands are low, then ideally, most of those energy demands can be met with fuel from fat. I don’t feel like it’s the best tool in the box, but if you’re relatively healthy and get bored easily, I think it’s ideal.

Get moving

Whilst an incredible potent method of exercising, this wouldn’t be my choice for someone just getting started. The rationale for this is two-fold. Firstly, to really get the most out of the high intensity work, you need a good strength base that de-conditioned people just don’t have. Secondly, the rapid transition between energy systems can be overwhelming for a lot of newcomers to the gym. As with anyone just getting started, the objective should always be to promote enjoyment of exercise, not terrify them six ways to Sunday. So whilst this is effective, I don’t feel it’s appropriate.

Feel like you’re doing something while disengaging mentally

Not for me. When I do EST, I have to be present for almost every rep, with the exception of the low intensity exercises. If you’re pulling 2 reps with your 3 rep max on a deadlift and then moving straight into 6 power cleans with an 8 rep max weight, you’d better be mentally present, otherwise you’ll likely injure yourself. Having said that, you won’t be thinking about work, house or spouse while you’re doing it. So if the goal is to switch off, then no, but if the goal is to shift your mental energy off something else, then yes.

Metabolic Training

Improve cardiovascular fitness

Without a doubt. The deliberately high energy demands of metabolic training, coupled with the variability in muscle group recruitment, means your body adapts quicker and you become fitter.

Improve body composition

Absolutely. For fitter individuals with a good work capacity, this is a great way of maximising calorie burning and creating a serious energy debt in the body. For people looking to get leaner, this is always the type of training I’ll progress them towards.

Improve athletic conditioning

This particular benefit is a hard one to assess. Whilst MT has a pretty good carryover to athletic endeavours in general terms, the degree of benefit will depend on the sport in question. In spite of that, every athlete I’ve trained has done this at some point, and all of them have seen improvements on the pitch or in the ring.

Improve lactic acid tolerance

Whilst MT will definitely improve your lactic acid tolerance, there are more specific methods out there. The main objective of MT is energy expenditure, therefore as one muscle fatigues, another would take over, allowing for more work.

Get moving

Hell no. Now I’m aware this point will probably be contentious, but I don’t think newcomers to exercise need or benefit from metabolic training. As many people know, newcomers make tonnes of progress in their first 4-6 weeks. If that’s the case, why run them into the ground to achieve it. I believe it’s far better to build the habit of exercising than go for gold from the outset. After all, you wouldn’t give large Marge the same programme as Usain Bolt, even if she wanted to become a sprinter. Scientifically speaking, their muscle fibre recruitment won’t be optimal either. That means they’ll be working their butts off and wearing themselves out, but because their central nervous system hasn’t learnt how to recruit muscle fibres effectively, they’ll potentially use less energy. The absolute opposite of the goal.

Feel like you’re doing something while disengaging mentally

Again, much like EST, you can’t switch off, but you can change the focus.

The following table gives my recommendations in a nutshell (cue Austin Powers flashback) regarding the suitability of each method for each goal. Be aware though that there may be considerations that I haven’t covered here. In which case, just use common sense.

 [table]

Cardiovascular fitness

Body composition

Athletic conditioning

Lactic acid tolerance

Get moving

Disengaging mentally

MB Steady state

Low-Moderate

Moderate

Low

Low

High

High

MB Interval training

Moderate

Moderate

Low

Moderate - High

Moderate

Moderate - High

Free steady state

Moderate

Moderate

Low - High

Low - Moderate

High

High

Free Intervals

Moderate - High

Moderate - High

Moderate

Moderate - High

Moderate

Moderate - High

Rhythmic Group Exercise

Low - High

Low - High

Low

Low - Moderate

Low - High

Low - High

Circuit training

Moderate - High

Moderate - High

Moderate - High

Moderate

Moderate - High

Moderate

Energy Systems Training

Moderate - High

Moderate - High

Moderate

Moderate

Low

Low

Metabolic Training

Moderate - High

Moderate - High

Moderate

Moderate - High

Low - Moderate

Low - Moderate

[/table]

 

One last point. I’ve had a number of emails asking what I do with my clients and whilst it depends on their goals, the following are pretty consistent in terms of what I don't do:

  • I don’t use CV machines (unless you’ve had a heart attack, open heart surgery, etc. and even then, it’s in the absence of enough space to walk)
  • I don’t prescribe steady state. Even for carb depleted or fasting clients. I’ll just have them do lower intensity intervals.
  • I don’t use EST with beginners, ever.
  • I don’t use MT at the expense of technique. If a client’s technique isn’t good enough (notice good enough, not perfect), I’ll sort that first. Otherwise, as they get fatigued, it’ll go very quickly from bad to worse.
  • I don't recommend a group exercise class unless I’ve seen it or know the instructor well enough to understand the type of class it’ll be. There’s too much variance out there. If you want to recommend classes to clients, I think you should make sure you know enough about them first.