Amazing Energy Systems!

Part 1:2

Next up in this series : Zone Intensity Training & How You Can Create Your Own Training Zones!!

The human body is an amazing machine! We have multiple energy systems within our bodies that provide fuel for our activities so that we can run, spin, jump and play at a range of speeds and durations. Although we are always using a combination of energy systems to move our bodies, there are two main methods that your body uses to produce ATP (energy currency of the body!) Aerobic and Anaerobic. The actual processes involved to create energy so that we can move our bodies, are highly complex, but this overview will give you an idea of what your body is up to on those runs and rides;)

Aerobic: means “with oxygen”. This energy system fuels your lower intensity, long duration, endurance workouts. The lower the intensity and the longer duration, the more it becomes fueled by the aerobic energy system. While you are sitting there reading this you are primarily using your aerobic system. The aerobic system is efficient and at low intensities you can go on and on and on without running out of steam (in theory). The aerobic system is fueled primarily by fat and research tells us that, in theory, we have enough stored energy in the form of fat to run, on average, 26 consecutive marathons!

Anaerobic: without oxygen. This is your higher intensity, short duration, energy system and it is made up of two systems: Lactic and Alactic. Too fast and too intense for the aerobic system to keep up with your energy requirements, these system use glycogen (carbohydrates stored in muscle) and other substrates as their fuel source. These fuels are finite and produce by-products that will build up and leave you feeling fatigued with increased effort so that you can only maintain high intensities for a limited period of time. Activities lasting less than 10 seconds are fueled predominantly by the Anaerobic Alactic system, where those lasting 10-60seconds are Lactic system driven. Beyond this the percentage begins to shift to greater and greater support from the Aerobic system. With an effective training program, the body actually learns to process and use these bi-products to produce additional ATP (energy) so that you can tolerate higher intensities and longer durations of high intensity work.

More Terms:

Aerobic Threshold. AKA Top of Zone 1 in a 5 zone training intensity system. The point/pace at which the body shifts from near pure reliance on the Aerobic energy system as it requires additional support from the Anaerobic system. You get what you train, and when you spend significant time training below your aerobic threshold (Zone 1 upper limit), some amazing adaptations occur in your body! Consistent Zone 1 training results in: increasing capillary networks, improving the bloods oxygen carrying capacity, increasing mitochondrial activity (energy producing factories in our cells), improving fat utilization and much more. The more effectively you train your aerobic system (below Z1 intensity), the better your body will become at using fat as a fuel source, allowing your muscles to spare precious, limited glycogen for your endurance events. WOW!

If you are training for an endurance event lasting more than 2.5 hours, training your aerobic system correctly is critical for your performance. In fact, 80-90% of your weekly training time should be spent in this Zone, below your Aerobic Threshold (yes, you read that right, total up your minutes and avoid wasted training time above Z1 in the 'grey zone'). Unfortunately, many athletes train too fast and end up training at too hard of an intensity during their Z1 workouts and therefor they will never reap the powerful, transformative benefits of true aerobic training. It can be hard to relate running and riding slower with getting faster, I get it. But man oh man, when you feel how transformative aerobic training is for both your endurance AND endurance pace, you will be a convert. Note: BE CONSERVATIVE during Z1 training so that you don’t mistakenly run above your aerobic threshold. No heavy breathing, no burning legs, should feel ‘easy’. Run slower if you are unsure and train on your own to avoid pushing too hard. 2-4/10 for intensity on the Rate of Perceived Exertion Scale.

Lactic Threshold aka Anaerobic Threshold. AKA Top of Zone 3 in a 5 zone training intensity system. A heads up that lactic acid has a bad wrap. Despite the rumours, it is not, in fact, lactic acid that creates fatigue in our muscles with sustained high intensity efforts. It is actually, hydrogen ions that create an acidic environment resulting in muscle fatigue. Lactate (it is not an acid) actually comes to the rescue and acts as a buffering agent to decrease this acidosis. As the effort increases, lactate floods the bloodstream to buffer the acidosis. Eventually, the production of hydrogen becomes greater than the bodies ability to process it and acidosis sets in. This is known as Lactate Threshold or Anaerobic Threshold, which correlates with an increased breathing rate, heart rate and burning sensation in the muscles. If this threshold level is exceeded, you will only be able to sustain the pace for a few minutes. Lactate Threshold usually correlates with the pace and average heart rate that you can sustain at hard effort for approximately one hour. 7-8+/10 on the RPE Scale.

VO2 MAX. This is the maximum amount, or volume, of oxygen that you can use at one time. We all have genetic potential/limitations but VO2max can be improved through training. Amazing adaptations occur in the cardiovascular system as the result of VO2max training, which contribute to a higher VO2max, speed at VO2max, improved endurance and the potential for a higher lactate threshold. WOW! 8-10/10.

Next up, let's chat about how to create and use Heart Rate, Pace and Power Training Zones!

Need a training plan to go along with all that new exercise physiology knowledge? I'm here for ya!  Check out my Self Directed Training Plans on the Training Peaks Store!

Train smart and have fun!

Cheers,

Sarah Seads