As the small collective of regular readers will have discovered, I’m a huge fan of fasted cardio for keeping fat at bay. Fasted cardio can be utilised at any time of the year, regardless of whether the individual is cutting bodyfat or building as much muscle as possible.
How do you make a bodybuilder cringe? Walk into the gym and shout cardio. Far too many trainers forgo the benefits of a regular cardio schedule as they are afraid. What exactly are they afraid of you ask? The answer – Losing muscle! I will admit that if cardio is approached with a carefree approach then undesired results are a possibility. Fuelling, intensity and the duration of cardio all have a major impact on the outcome. This is where the science comes in.
Energy Systems
We have 3 energy systems that get called upon to create energy. These 3 are as follows:
- ·TThe ATP-PC system
- ·TThe Anaerobic system
- ·TThe Aerobic system
Why 3? The human body being a clever little so and so only has survival in mind. As a very flexible unit your body can wind down calorific usage in times of starvation, increase usage and storage in time of surplus, create energy from any macronutrient via a whole variety of inner chemical wizardry and even choose which type of fuel to burn when faced with energy demanding situations. The entire above are carried out with the utmost efficiency. Each of the 3 energy systems is unique! They all have different attributes and roles that will be called into action depending on the type of exercise used.
The ATP-PC system (adenosine tri-phosphate phosphocreatine) is predominantly used for exercise that is no longer than 30 or so seconds in duration. Stored levels are very small and as such can only provide energy for a short duration. Weight lifting and other short burst exercise like sprinting will utilise the ATP-PC system to its maximum effect. Once it’s depleted it’s onwards and upwards to the anaerobic system.
Taking the baton from the ATP-PC system, the anaerobic system has a little more shelf life than its predecessor. Starting in and around the time of the ATP-PC system, the anaerobic system will take fuel from stored muscle glycogen and carbohydrate intake for its 15 minutes or so stint of stardom. Although this system is a quick fire way of producing energy, it lacks the efficiency to go the distance! Producing only 2 ATP molecules from 1 glucose molecule, as opposed to the possible 38-200 molecules produced from the aerobic system. Needless to say it is heavily relied upon by us weight training heroes.
Last but not least is the slow but efficient aerobic system. I like to call this the “Mr Fusion” energy system after Doc Browns Delorian which would run off of anything you shoved into the fuel tank! It’s important to note that the aerobic system is the only one which will readily use carbs, muscle tissue and most importantly fat for fuel. As to which gets burnt is dependant on fuelling, intensity and duration of exercise. Here are a few graphs to give you an impression:
This is a beautiful graph! Easy to read and understand. It is to be understood that a mixture of glycogen and fat will be burnt for fuel; however it is quite evident that the ratio can be swung in a more favourable direction if one was to alter the intensity of their exercise. Onto duration:
The above graph gives us a visual clue to how exercise duration effects which fuel we burn. Please take the timeframe with a pinch of salt as it has been said that approx 15-20 minutes is required to shift from the anaerobic glycogen burning zone, into the more favourable aerobic zone to which will start using adipose tissue (fat) for fuel.
Before the cardio happy bunny interprets from the chart that fat burning is awesome approaching the 2 hour mark, please bear in mind that somewhere around the 45 minute mark glycogen stores will start to diminish and other sources like amino acids will be broken down for fuel. This is bad for the aspiring bodybuilder as your muscle tissue is a prime candidate to be placed in the firing line.
What has the muscle conscious individual learned so far? Cardio should be performed for no longer than 45 minutes max and intensity should be kept fairly low to throw the fuel burning ration more towards fat burning.
Why Semi Fasted:
Exactly why do I recommend the semi fasted approach? Besides from the testimonies of many trainers and personal results I will have to lean on a few little scientific crutches to get the job done:
"A study carried out at Kansas State University (Wilcox, Harford & Wedel Medicine & Science in Sports and Exercise, 17:2, 1985), indicates that a kilogram of fat will be oxidized sooner when exercising in the fasted condition in the morning than when doing the same exercise in the afternoon. By measuring respiratory gas exchange, caloric expenditure, and carbohydrate and fatty acid metabolism, these researchers showed that the mass of fat burned during aerobic exercise amounts to 67% of the total energy expenditure achieved when the same exercise is done later in the day or in the fed state."
Besides the above we can take advantage of the lack of fuel and natural dip in morning insulin levels to more effectively promote fat burning. This fasted environment is great for coaxing a larger amount of fat from stores for the furnace!
Although fully fasted is ok if kept under 45 minutes and at a real low intensity, I would recommend 5-10g of BCAA’s to sip on during morning cardio. They will not only symbolise the end of the fast but also spare and hard earned muscle in the process. A small serving of a decent grade whey 80%+ could also do a similar job without hiking insulin too much…
No comments:
Post a Comment