ENERGY SYSTEMS TRAINING: CARDIO AND FAT LOSS

Human Energy Systems for Fat Loss and Fitness

Cardiovascular training, Aerobics and what really works

Cardio or CV training as you’ll often hear it called or even aerobics in gyms is actually a misnomer for the purpose often intended. True Cardiovascular training does just that – isolates as much as possible training endurance in the heart, lungs and blood distribution. There is absolutely nothing wrong with this type of training at all however we have to be clear as to what we are trying to achieve and the best ways of heading towards that goal.

For the purposes of fat loss, health improvement and general performance training for a marathon may not be ideal. In fact training for a marathon generally has one main adaptation – it makes you better at running marathons! But Marathon runners in general carry very little lean muscle tissue and are rarely the leanest people on Earth (though no doubt incredibly fit for purpose). If you are planning on engaging in long distance running or cycling for example then you should train that way. If you want to build a physique that has quality muscle definition and consistently low body fat levels then you may be more concerned with the more properly termed ‘Energy Systems Training’.

Burning out

Your body can only apply so much energy to training before it becomes over trained becomes stressed and damaged and results grind to a halt. Your body has a finite amount or ‘nervous fatigue’ it can endure. Imagine small, minimal exercises only involve a few localised nervous fatigue patterns (e.g. bicep curls might make your arms fatigue but it’s primarily local), you can get away with a certain amount more than big exercises or outputs of energy (e.g. a high intensity squatting session fatigues legs, back, shoulders etc but also causes entire systemic central nervous fatigue) – you get more training effect but you also spend more of your limited recovery ability. With excessive endurance style training though you are not only fatiguing your nervous system but producing a lot of cortisol – the tissue breakdown hormone. This is an essential hormone that reduces stored energy to fulfil a current need. Unfortunately chronically elevated cortisol levels means muscle cannibalised for energy and very rapidly a decline in muscle size and power output. It’s also not a great long term health condition which is why ultra distance runners are generally a pretty unhealthy lot (there is a difference between being fit and healthy. Fit simply means you can perform a task very well, healthy is about avoiding injury, disease and stress related long term damage.)

When it comes to training for the benefits of Energy Systems Training you are looking at lowered blood pressure, better cholesterol profiles and just as importantly reduced ‘visceral’ fat (this is the highly dangerous fat that coats the abdominal organs and is most threatening to your health) not to mention the subcutaneous fat that smothers our hard built physiques. This type of training can really make a difference to our health that may not be covered by resistance training at all or at best partially. So how to balance the fat busting, health promoting good side with the muscle eating, cortisol raising dark side?

First it helps to understand the main energy systems of the body.

Energy Systems in humans

Your body has three primary energy systems. They work in a cascade fashion meaning the first always kicks in first whether you are extending an arm or sprinting all out down the street, when this exhausts the next takes over and so on.

1. Adenosine Triphosphate-phosphocreatine (ATP-PC)

2. Anaerobic Glycolysis

3. Aerobic Metabolism

1) With the first the ATP is the immediate use energy found in muscle tissue and the PC is what can rapidly generate more (you may notice the word creatine in there – yes this is the same thing as the supplement, yes – it’s already a part of your cells, the supplement just aids the production of more ATP in short bursts)

This form of Energy System can be ignited virtually instantly. This allows explosive movement and all out effort but even for a mild exercise this system is always called in first. It’s your body’s first response to a nervous impulse ordering movement. Still this incredibly powerful and explosive energy system requires no outside substance or aid, it’s totally self reliant (although yes creatine supplementation can improve it slightly). Even with all this ATP exploding out energy and the PC converting more on demand your body can manage between 15 and 20 seconds of maximal effort using this system before it is exhausted and needs time to recharge and re supply itself. This system would best represent an explosive weight lifting set or the initial burst of a 100m sprint for example.

2) After that first initial burst looks like exhausting your ATP system your body can operate at a slightly lower level by moving over to anaerobic glycolysis. Anaerobic meaning ‘without oxygen’ this is the strange middle system that is not truly independent and explosive but also not reliant on the oxygen dependent aerobic system. This system is the crossover and makes fresh ATP fuel for muscles using glucose (hence glycolysis). Glycogen is the stored sugar in muscles and represents the next most powerful fuel source the body can see around. Unfortunately without oxygen present your body has to use pyruvate to start conjuring up amongst other things lactic acid. Contrary to the old popular (but still persistent belief) lactic acid is actually a powerful fuel source for muscle tissue and can offer ATP fuel for up to 10 minutes in a well trained athlete. Unfortunately due to some complex metabolic limitations at this stage even the best athlete cannot continue and will revert to the final energy system at least temporarily.

3) When your body has exhausted all other options it will begin to use that fundamental oxygen to break down carbohydrates and fats for fuels. This system is thousands of times more efficient than its predecessors unfortunately it is also far weaker in energy output. Imagine it as the economic low fuel consuming eco car versus the hyper-tuned sports car of the ATP-PC system which produces huge power but burns itself out faster too.

It is still possible for your body to return down the energy system routes once a period of renewal has undergone metabolism. For instance if you began a bike ride with a crazy all out sprint, your ATP-PC system would be burnt out in 20 seconds, then your speed drops, you breathe harder and the anaerobic glycolysis kicks in. After 10 mins of max effort your body moves from sprint to endurance mode and slows again but becomes more constant and efficient. It is still possible that should a hill climb or sudden overtaking sprint be required our body could reactivate the second energy system and with acute training and enough time elapsed between all out sprints it could get a few more seconds from the ATP-PC system.

Integrating fat loss and physique control

Aerobic metabolism burns a lot of calories and can be sustained for long periods of time even by relatively untrained individuals. It also takes energy from both carbohydrate and fat stores so we can be sure of burning up some fat. Unfortunately the long distance endurance use of aerobic metabolism robs from our muscle building efforts if overused and offers none of the specialist fat burning benefits of the anaerobic glycolysis. So what’s the answer? Well for anybody interested in both the health benefits and a leaner physique combining both is essential.

Anaerobic glycolysis produces lactate which although it burns less fat during exercise prompts the body to store more protein in starved muscles and continues to burn fat long after the exercise has been completed. Aerobic metabolism means we can burn fat during the effort too. With both utilised we can cut down on the cortisol overload, burn a lot of calories and fat straight away and set up our body for all day fat burning activity.

Our bodies contain four main classes of fibres. The thickest and largest tend to be dominant in those training for larger, explosive activities while the smallest and most efficient are dominant in endurance activities. It is also possible for the body to emphasize these fibres given the correct stimulation. For someone who runs long distance over time the body will come to emphasize the smaller, thinner fibres and the resulting physique will match it. If you are looking to maintain a more muscular of powerful body you want to avoid falling into too much endurance work.

For the purposes of physique improvement and overall health Energy Systems training should be limited to about 20 minutes in total. 3 sessions a week will usually suffice for most goals. If you prefer more sessions you will need to reduce the time of each to limit cortisol production. Of course some people will still find that they can complete more without over training (and some may over train even at this modest output).

Initial targets

Intensity in cardio type activities can be quite hard to judge. Whereas some people push themselves too hard too fast, others think they are working hard while holding back way too much. For the purposes of intensity in these activities we usually adopt a target heart rate.

Maximum heart rate (BPM) = 220 – Age in years.

For example a 30 year old man would have a max predicted heart rate of 190 beats per minute.

This represents the most you should generally push your heart rate to for any extended period and should be more or less accurate to what happens during a max effort all out run or cycle sprint. Of course not everybody will fit neatly into this simple equation but it does offer a good sample target range.

Aerobic work that still maximizes fat burnt during exercise is usually pegged at 60% of your maximum heart rate.

For example our 30 year old man would be predicted to aim for around 114 BPM heart rate for aerobic metabolism activity.

However we already know that the lactic acid producing anaerobic glycolysis system can continue to burn fat after exercise and has a host of muscle sparing effects. However we would be looking at closer to 80% Max Heart rate to engage this system.

Continuing our example our 30 year old would need to move up to 152 BPM to really push into the AG system.

Example programmes

Very mild warm up consisting of stretches and then 3 minutes of very low intensity jogging/cycling/stepping etc.

3 sessions per week.

Duration 20 minutes.

Undulating output of 3:1 60% to 80% max intensity.

This essentially means for 3 mins complete work at 60% intensity and then perform 1 minute at moving up to 80% intensity.

Every two weeks add 5% to the intensity output until you reach 3:1 ratio of 70% to 90% intensity.

When this is accomplished return to 60% to 80% but alter the workload to 2:1 meaning more 80% peaks per workout. Continue this with the same 5% progression.

Repeat at 1:1 work sessions. At this stage once you have reached the maximum undulating effort you may wish to consider moving to true HIIT (High Intensity Interval Training) which involves extreme sprints involving the explosive ATP-PC system. This maintains much of the fat burning and health benefits of the main system but adds in athletic performance for power sprints and can help maintain or even increase muscularity while still minimizing cortisol and over training.

If you simply have little time to spare and want maximum results and maximum fat loss you can graduate to HIIT immediately after 4 weeks of careful build up to ensure your body is prepped for it.

HIIT High Intensity Interval training

HIIT offers time limited trainees the perfect way to engage all three energy systems in a single exercise bout without over training. It’s a serious way to eat fat up fast as well as building power and explosive strength and still avoid cortisol overload or reduction in explosive muscle fibre ratio.

The essential idea is an old one of ‘sprints’ with recovery low intensity movement in between. The most basic form would be a 3 minute warm-up at 60% intensity followed by a 6:1 work ratio of flat out sprints versus walking or very low intensity jogging. As the ATP-PC system will not really offer much use beyond 20 seconds full flat sprints should be limited to timed 20 second efforts. In this way a 20 second sprint would be followed by 120 seconds (2 minutes) of minimal effort.

Clearly, even maintaining 20 minutes of maximum output there are lots of parameters for progression here.

1. Work ratio. The 6:1 ratio can be steadily reduced until eventually reaching a 1:1 with a 20 second sprint followed by a 20 second slow jog.

2. Sprint intensity. The overall maximum speed of the sprints can be increased. This is easiest to measure on a treadmill or computerised bike however if you can find someone to time you track sprints offer a more direct ‘feel’ and real world crossover performance. Each session one sprint can be improved by 0.1 mph. This doesn’t sound much but over the weeks you can drastically improve sprint times and overall effort.

3. Jogging intensity. The actual output of the interval breaks can be wound up. Initially don’t worry too much about the actual jogging, as the sprints will be exhausting enough as it is. However once you begin to turn some of the jogs into 70 – 80% intensity running you’ll be hammering all your energy systems like no other activity.

4. Sessions frequency. Although 20 minutes is still the maximum HIIT duration (and you can begin at only 5 minutes if you wish to ease yourself in) because the energy systems crossover you should be fine to include more sessions per week up to a maximum of 14 sessions (every day of the week, morning and evening). This would be an extreme output and unlikely to be of much use to anybody except competitive athletes or those in a military setting. However even aiming for a higher frequency can make vast differences to your health and body in a short time.

Be careful not to try using all three progression methods at the same time or each session will be just too much of a jump up for you. Choose one at a time, or one per session or week to bring up. Eventually you will reach a peak performance that will undoubtedly outweigh virtually anybody you’ll come across and have the physique to show for it.

Be warned that continual ATP-PC sprinting and lactic acid producing high intensity running may often make you feel nauseous as the body attempts to move between energy systems. It can often be helpful to perform this type of training first thing in the morning before eating when the body cannot rely on food glycogen and must revert to its stored fat. Also an empty stomach has less to throw up!

It is important to progress and good progress means pushing yourself but be aware that some people push too hard and too fast and as healthy as energy systems cardio routines are more effort than your body can currently handle can be as dangerous as doing nothing at all. Finding the balance can take some time but keep a check on your overall body fat levels as well as your motivation for training. A sudden drop in motivation can often be a signal of extreme nervous system fatigue and indicate backing off and resting for a few extra days may be essential.

For further energy system metabolic training and advanced techniques see the ‘Advanced Techniques’ articles.