Cardio. CV. Aerobics. Energy system work. So many names for the same thing! And with so many cardio options available, it’s tough to decide which method is best. Much of what is written about cardio exercise is biased towards one approach or another and is often based on the authors’ preference and back ground. In this article I’d like to provide you with an independent view of cardiovascular training so that you can make an educated choice as to which method is best suited to your goals.
What is cardiovascular exercise? For exercise to be truly considered cardio, it should consist of steady-state activity which uses large muscle groups in a rhythmical manner and elevates your heart rate to somewhere between 60-90% of your maximum heart rate. Generally, activities such as jogging, running, power walking, cycling, swimming, group exercise classes, rowing, and using a skipping rope are the mainstay of aerobic activities but ultimately, any activity which significantly elevates the heart rate for an extended period of time can be considered aerobic training.To be honest, the modality used makes very little difference and you should choose the one you like most/dislike least!
How hard? Cardio training is normally performed for an extended period of time so it’s important to choose an exercise intensity that is hard enough to be beneficial but not so hard that it becomes necessary to stop. It is generally accepted that the benefits of aerobic exercise are gained from working at between 60-90% of an individual’s maximum heart rate (MHR) and many people rely on monitoring their heart rates as an indicator of exercise intensity.
You can calculate your Heart Rate Training Zone (HRZ) by performing the following calculations…
Simple Karvonen Theory
220 – your age in years x 60% 220 – your age in years x 90%
e.g. HRZ for a 40 year old 220 – 40 = 180 x 60% = 108 bpm 220 – 40 = 180 x 90% = 162 bpm
Heart Rate Reserve (takes into account elevated fitness levels associated with a lower resting heart rate)
220 – age in years – resting heart rate x 60% + resting heart rate 220 – age in years – resting heart rate x 90% + resting heart rate
e.g. HRZ for a 40 year old with a resting heart rate of 60 bpm 220 – 40 = 180 – 60 = 120 x 60% = 72 + 60 = 132 bpm 220 – 40 = 180 – 60 = 120 x 90% = 108 + 60 = 168 bpm
These numbers represent the lower and upper range of your HRZ. Going below 60% will essentially negate many of the benefits of exercise as it will be too easy where as going above 90% will take you into the anaerobic zone where lactic acid will start to rise and you’ll be forced to slow down and stop…and it hurts too! We’ll look and anaerobic training later though as it’s a very useful exercise tool. To keep an eye on your heart rate while exercise you have a number of options available…you can use a heart rate monitor, you can take your pulse manually at either your wrist (radial pulse) of at your neck (carotid pulse) or, if using gym-based cardio equipment, many machines have built in hand sensors which measure your heart rate although some are more accurate than others. However, the calculations above are not infallible – some people don’t fit into either of these systems and may find that their HRZ makes exercise either too easy or too hard. Luckily there are a couple of other methods we can use to monitor exercise intensity…
The Rate of Perceived Exertion Scale
The Rate of Perceived Exertion Scale (RPE for short) was designed in the 1960s by Gunnar Borg – a Scandinavian exercise expert. He devised a scale with which to prescribe aerobic exercise to his athletes based on how they felt while training. The original RPE scale went from 6 (absolute rest/inactivity) to 20 (maximum exercise intensity). Why a scale of 6 – 20? Borg’s athletes had an average resting heart rate of 60 bpm and an average maximum heart rate of 200 bpm so he just knocked of a zero. It was found that, with some practice, it was possible to estimate how hard an athlete was working based on how they felt and this corresponded quite accurately to their corresponding heart rates. For many people, the classic 6 – 20 scale is a little awkward to use so it has been simplified and adapted to suit the general exerciser…
1. Inactive/at rest
3. Very light
9. Very heavy
As a general rule of thumb, steady state cardio should be performed at an RPE of 4 – 7 for maximum benefit. Exercise below this level won’t cause much in the way of fitness or health benefits and above will mean approaching the anaerobic zone.
Test Our final method for assessing exercise intensity is the talk test. Quite simply, while exercising in your aerobic HRZ you should be able to hold a conversation with regular pauses for breath every couple of sentences. If you can only manage single word responses then it’s likely you are working too hard and if you can manage whole paragraphs without pausing for breath then you’re probably not working hard enough. Combine RPE with the talk test and you should have no problem making sure you are working at the correct intensity to get the maximum benefits from your exercise.
How long? How often?
The American College of Sports Medicine (ACSM) recommends 3 bouts of cardio exercise per week for a minimum of 20 minutes per session at between 60-90% of MHR to a) improve fitness and b) reduce mortality. Doing more is not necessary for health purposes but if performance enhancement (elevated fitness levels) is your goal then increased frequency and duration are likely to be necessary. Even rust-stained iron pumpers should make sure they get their 20 minutes 3 times a week for protect themselves from the likes of CHD and other diseases of the cardiorespiratory system.
Different approaches to aerobic training
So now you know how to monitor your exercise intensity and how long/how often to exercise, let’s look at the different ways you can choose to perform your aerobic activity…
LSD – and no, not the drug! LSD stands for Long Slow Distance training and it the method that most exercisers “fall into” when they embark on a cardio training programme. LSD training is exactly as it sounds – performed at a relatively slow pace for extended periods of time. LSD training builds base level aerobic fitness and conditions the body for extended workouts. LSD is performed at around 60% of MHR or around RPE level 5 and may be performed for as long as an hour or more. LSD training has the advantage of not being overly exhausting but on the down side requires a greater time commitment compared to some other methods we’ll discuss later. LSD is a vital component of training for marathon running and long distance cycling but while a necessary part of endurance athletes training, many fitness enthusiasts use LSD for weight management in the hope that it will result in substantial amounts of fat loss. While exercising at LSD pace fat provides the primary source of energy however, fat is so energy dense – 9 kcal per gram – that even extended workouts result in only relatively small amounts being oxidised (burnt). Regardless of pace, running a single mile uses around 100 kcal and 1 pound of excess body fat contains about 3,500 kcal so to lose a pound through slow paced aerobic exercise alone it would be necessary to run 35 miles! Chances are that’s more than most people run in 2 weeks! LSD training (and remember LSD can be applied to cycling, rowing, stepping as well as running) is great for developing base level aerobic fitness but when it comes to fat burning/weight management, there are other methods which will be more successful and efficient.
Fartlek – funny word but serious training method! Fartlek means speed play in Swedish and that describes perfectly our next method of cardio training. The basic premise is to run (or cycle, row etc) at a variety of paces which are selected at random. The exerciser may walk, jog, run or sprint for a variety of distances and durations over the course of a workout until the exercise time period has elapsed or a predetermined distance has been covered. Physical landmarks such as lampposts, street signs or trees is a great way to organise a Fartlek workout e.g. after jogging for 5 minutes to warm up alternate between running hard for 3 lampposts and slow jogging for 1 or jog 1, run 1 sprint 1 and repeat. Alternatively, work periods can be controlled by counting the number of strides or time elapsed or a combination of the above. The variations are endless and can be just as easily applied to cycling as they can to running or any other cardio exercise modality. The intensity of a Fartlek workout can be easily altered to suit an individual’s fitness levels by moderating the amount of high intensity exercise compared to lower intensity work – in other words the less fit the exerciser, the slower jogging and brisk walking will be performed. Fartlek, done for a shorter duration than LSD but at a higher overall average pace, is a good fat burner because of the periods of higher intensity training which triggers a phenomenon called EPOC (Excessive Post Exercise Oxygen Consumption) which will be discussed later.
FCR – time to hit a higher tempo! FCR stands for Fast Continuous Running but, as with all of our cardio training methods, this approach lends itself well to just about any exercise modality. FCR is just like it sounds, working hard at a high constant pace. On our RPE scale, FCR would score around 7 or 8 or about 85-90% of MHR and is the highest sustainable level of aerobic activity – think red lining your car just below the point where the engine will blow! Some refer to this as tempo training and others anaerobic acid threshold training but regardless of what it’s called; FCR is a tough but generally shorter workout. The idea is simple – run (or cycle or row etc.) as fast as possible avoiding going so fast that you are forced to slow down because of fatigue. Lactic acid (one of the by products of anaerobic energy production) is literally bubbling under the surface and going any faster will result in having to slow down or stop. FCR is (or should be) a constant battle to maintain pace – even though the body is probably saying “slow down!” Because of the large accumulation of lactic acid in the blood, FCR is a supreme fat burner because of EPOC.
When lactic acid accumulates in the blood, the aerobic system has to work overtime to clear it out once exercise comes to an end. This “after burn” is responsible for an elevated metabolic rate (energy expenditure) at rest. The body is literally in overdrive working to clear unwanted lactic acid from the system and, as a result, burns a whole load of energy not just during the workout but also in the hours (yes HOURS) afterwards. The metabolism may be elevated for up to 48 hours after a hard lactic acid inducing workout which results in substantial energy costs and potential fat loss. Pretty good for a shorter workout! LSD (long slow distance) training causes minimal EPOC and, as a result, is not so efficient for fat loss.
FCR is an excellent training method for improving higher end aerobic fitness, teaching the body lactic acid tolerance and in training athletes involved in shorter, more intense sports like boxing, middle distance running, rowing or martial arts. It goes without saying that because of the advanced nature and demands of this type of exercise; FCR is something to work up to and should only be attempted after establishing a base level of aerobic fitness via LSD and Fartlek training.
Interval training – the clock is your coach! Interval training can be defined as “periods of higher intensity work interspaced with periods of rest” and is a very useful and flexible training approach which, with modifications, is suitable for everyone from the beginner exerciser to an Olympic champ. By manipulating the training variables i.e. speed, distance covered, length of recovery etc it’s possible to design interval training programmes for just about anyone…
1) E.g. Beginner client – low level of fitness Power walk up hill 3 minutes Slow walk on flat 2 minutes Repeat 4 times
2) E.g. Intermediate client – good base fitness Row 1000 meters as fast as possible Very slow row for 2 minutes Repeat 6 times
3) E.g. Advanced client – very high level of fitness Sprint 400 meters Jog 100 meters Repeat 10 times Work vs.
Aerobic intervals With aerobic intervals (up to 90% MHR) generally workouts are on a 1 to 1 work to rest ratio or possible 1 to .5 e.g. Run 3 minutes, resting 90 seconds to 3 minutes between efforts.
Anaerobic Intervals Workouts that exceed 95% of MHR will often require a longer rest period between efforts so 1 to 2 or 1 to 3 work to rest intervals are the norm e.g. sprint for 30 seconds, rest for 60 – 90 seconds.
(Please note these are only guidelines and work/rest intervals can be manipulated freely to suit the abilities of the individual exerciser)
Regardless of the standard of the client, the interval principle is the same – alternate periods of higher intensity exercise with periods of recovery. Interval training allows significant overload of the cardiorespiratory system which will result in good increases in the both anaerobic and aerobic fitness while also being, according to some experts, the ultimate fat burning workout because of very high degrees of EPOC. Certainly, a hard interval session can result in very high heart rates and elevated body temperature for many hours after exercise has concluded which is a good indicator that the metabolism is very “revved up” even at rest.
As high-end interval training can be so demanding, it is very important to progress into it gradually. It’s certainly not a good idea to attempt workout number 3 if you have little or no running experience. Make haste slowly and start your interval training regime with the intention of gradually increasing your workload over the coming weeks – your body will thank you for it!
Putting it all together So now you know about the various cardio training methods let’s briefly look at how you can incorporate them into your weekly schedule… If your chosen sporting activity is very start/stop like basket ball or rugby, the majority of your cardio training time would be best spent performing a variety of interval training whereas if your sport involves fast but continuous effort e.g. 5km running or similar, FCR should be the dominant feature of your workouts. If you are more involved in activities that take place over longer durations e.g. long distance running or cycling then LSD will be a necessary tool for you to utilise on a regular basis. If however you just want to add some variety to your current cardio routine I suggest the following template as a good staring place.
Day 1 FCR
Day 2 LSD – recovery/easy pace
Day 3 Rest
Day 4 Intervals
Day 5 Rest
Day 6 Fartlek
Day 7 Rest
If you choose to design your own weekly template it’s important to remember the following…
o Avoid having too many intense workouts in a row without any rest/recovery time as you may feel burnt out
o Monday follows Sunday! Don’t begin AND end the week with hard or identical workouts.
o It always look easy on paper – don’t be afraid to change your plan if you underestimated its intensity.
o Make haste slowly – only increase your workout durations by around 10% a week. Greater increases than this may lead to injuries and you can’t train if your are injured.
o Cross training is a great way of making sure you don’t over stress any one particular part of your body. By mixing your exercise modalities e.g. running, cycling, rowing, swimming etc, you can avoid overloading and possibly injuring your limbs.
o Choose the exercise modalities you enjoy – running is not compulsory! You can swim, cycle, step, skip, row, walk or whatever suits you best. If it hurts it’s probably not doing you any good.
o Remember that cardio is not the golden goose of exercise – it’s important to make sure that you also perform your strength training, flexibility work and core work otherwise you may find yourself very fit but as weak as a kitten with the posture of Quasimodo and as flexible as concrete!
So now you know about cardio exercise. Introducing some of the methods described in this article will hopefully get you out of your cardio rut and push you on to new, higher levels of aerobic fitness. Oh, and by the way, if you are one of those people I see in the gym every morning walking sedately on the treadmill while reading a newspaper…you’re wasting your time!!!