UWA Sport Masterclass: Aerobic Training
Cardio…. What is it?
Cardiovascular training or Aerobic training can be defined as physical exercise that depends on the aerobic energy system. In other words, aerobic training is any exercise that features the use of oxygen to adequately meet the energy demands of that exercise. An easy way to remembers is aerobic = "air-robic!"
What do you first think of when you hear "cardio training"? If you thought of running, cycling, or any other activity where you feel puffed out, you'd be correct!
Training our cardiovascular system is so important not only for our physical health but also for (as the name suggests) our cardiovascular health. Our cardiovascular system is made up of arguably the most important organs in our body - the heart and lungs. Without either of these, our bodies would simply fail to operate. The lungs are responsible for bringing oxygen into our bodies and sending carbon dioxide out. Our heart then takes this oxygen and transports it around our bodies through the blood, supplying all areas with oxygen needed to function.
Improving your aerobic fitness has also been proven to help lower blood pressure and cholesterol as well as reducing the risk of developing cardiovascular disease, certain types of cancer, diabetes and obesity.
Benefits
Decrease fatigue in daily activities
Increase cardiorespiratory function
Decrease blood lipid profile
Increase immune function
Increase insulin sensitivity
Decrease body fat
Increase sense of well-being
Decrease risk of:
Coronary artery disease
Some cancers
Hypertension
Type II diabetes
Osteoporosis
Anxiety
Depression
The American College of Sports Medicine recommends that we should be training aerobically 3-5 days per week at an intensity of 55-90% of our maximum heart rate.
NOTE: If you want to figure out what your approximate maximum heart rate is, take your age away from 220. For example, if you are 21, your maximum heart rate should be around 199bpm.
A typical training session should last around 20 - 60 minutes depending on your intensity and whether it's a continuous effort or if it's intermittent.
What Happens During Aerobic Training?
During aerobic training, our body undergoes a range of central and peripheral adaptations and physiological changes. Acute changes are short-term effects such as response to exercise and immediate/transitory adjustments. As you continue to progress with your aerobic training, you will begin to notice some chronic (long-term) changes such as an adaptation to your training - it will feel less difficult, the imposition of deliberate stimuli and enduring changes to your work capacity - you will be able to train harder for longer.
The aerobic adaptations you will experience all relate to increasing provision, extraction and utilisation of oxygen for the generation of ATP (adenosine triphosphate - our main source of energy!). One of these adaptations include respiratory muscle training, allowing us to maximise the amount of oxygen intake during exercise.
Aerobic training also triggers cardiovascular adaptations such as cardiac hypertrophy - increase in mass and volume of the heart! Our hearts are made up of muscle, the more we train this system, the more efficient our hearts become. The left ventricle increases in cavity size and wall thickness and our stroke volume (amount of blood the heart pumps out) increases as well. After aerobic training, our heart rate is lower at rest and during submaximal exercise, however, remains unchanged during maximal exercise.
Below is a summary of the central adaptations that occur after we regularly undergo aerobic training:
The muscles are where majority of peripheral adaptations occur. After aerobic training, all muscle fibres increase in their existing aerobic potential. Type I fibres (aka slow twitch fibres) experience hypertrophy - increase in size of muscle cell. There is also a conversion of Type II fibres (aka fast twitch fibres) from IIb fibres to type IIa fibres.
Mitochondria within a muscle cell increase in size as well as number which causes an overall increase in mitochondrial density within a cell. This then leads to an increase in the cells' capacity to aerobically generate ATP.
Below is a summary of the peripheral adaptations that occur post-aerobic exercise:
How to train/maintain Aerobic Fitness
Now that we have gone through everything that happens to us on the inside while training, we can now go through and learn how we can actually train and maintain our aerobic fitness!
Let's firstly introduce the Big 4, swimming, cycling, walking and running! These four methods of cardio training are the most efficient and will be the best at providing results. They all utilise the major muscle groups and sufficiently work the cardiovascular system.
Walking
Walking, despite being low intensity in nature, is still a fantastic way to exercise. The best part is that there is no special requirement for you to progress beyond a brisk walking pace. Walking is a lower impact option of aerobic exercise that involves less impact stress on muscles and joints (1-1.5 x body mass vs. 3-4 x for running).
Walking has many pros to it including; little need for equipment (only shoes), simple and easy, plenty of variety - different locations (beach/bush trail/etc), as well as less injury and soreness post exercise. Some cons of walking are that walking has a lower energy cost, meaning that to burn the equivalent amount of energy (calories) to running, you will need to increase the duration of exercise. Walking does also take more time to increase your fitness levels. To increase fitness, introduce hills, combine with short bursts of running, or try different surfaces (sand, soft tracks, cross country etc.).
If you are working on weight loss, try increasing the duration of your walk to at least 45-60 minutes per day.
Cycling
To effectively cycle for aerobic fitness, you must cycle around two times as fast as a run to achieve a similar working heart rate. Pros of cycling include a variety of locations/tracks, increase in leg strength and endurance, as well as incorporating transport with exercise. The cons that you will need to consider are equipment cost, the occurrence of bike accidents/falls, an intermittent energy cost as well as a lower energy cost compared to running.
Cycling comes with some equipment and training considerations as well. You need to ensure that your bike is set up correctly with your seat and handlebars set at the right height, knowing how to take corners properly (inside pedal up as you turn corner), braking, as well as use of gears. You will also need to think about the environment in terms of busy roads/footpaths, hills, weather (wind/rain). Try incorporating Fartlek, interval or continuous aspects to your training to change it up!
Swimming
Energy expended by swimming a given distance is four times greater than running the same distance! For example, if you were to run 100m, you would find it much easier than if you had to swim 100m. Females have approximately 30% lower energy cost when swimming compared to men as they have better buoyancy.
Pros of swimming for aerobic fitness include having the lowest injury rate of all of the Big 4, you can avoid battling heat (especially in summer when its 30+ degrees outside!), it's good for the spine as the is less tension and stress placed on it during a swim compared to a run, and if you are injured, there's a strong chance that swimming (even water walking) can help maintain fitness levels. Cons of swimming to be considered include needing to have sufficient swimming skills, the need to access a pool and the cost involved, and the possibility of eye/ear irritation.
For less experienced swimmers, try a mixture of swimming and walking/jogging in your program. Focus on technique improvement and gradually increase to include more swimming. For more advanced swimmers, try continuous, fartlek and interval style programs and incorporate them into your training.
Running
For the time invested, running will return the greatest energy cost as it has the effect of carrying your body weight. During a run, energy cost is largely independent of speed if it's below the anaerobic threshold i.e. the same energy will be expended if you run the same distance "faster" or "slower". Running on soft sand increases your energy cost by 50% compared to running the same speed on grass!
The pros of running for aerobic fitness are that you need minimal equipment, there's plenty of variety in terms of location, surface etc., and running proves the best energy cost return. The downside to running is that it can increase risk of injury as well as soreness post-exercise.
If you are just easing into running, try starting with "continuous" aerobic exercise (4-12 weeks). After that you may want to start introducing interval or Fartlek running to change it up and stimulate further improvement.
Different Programs
Fartlek training is a continuous exercise session with short bursts of increased speed (2/3 to 3/4 max pace) alternating with periods of easier effort for recovery. For example, in a 30-minute session, there is a 30 second faster effort every 2-3 minutes. During a Fartlek session, your heart rate will fluctuate (higher bpm during faster efforts and lower bpm during recovery periods).
Interval running are aerobic not anerobic. You want your intensity to be around 50% to 75-80% of your maximum pace with a work:rest ratio of 1:2 or 1:3. During rest periods, it is best to opt for an active recovery (i.e. walking) rather than a pure rest-recovery.
Progression and Maintenance
Initiation Stage (3-6 weeks)
To develop the habit of exercise
Lower intensity (40-50% VO2R)
Shorter duration (15-30 min)
High frequency (5-6 sessions/week)
Improvement Stage (6 months)
Progressive overload each week
Small individual increments in F, I, and D
Increase in weekly training volume <10%
Monitor benchmarks of progression
Maintenance Stage
Enjoyment and reappraisal
Diversify program
Different modes
Can reduce frequency and duration
How to Test Aerobic Fitness
There are many aerobic fitness tests out there that can tell you what your aerobic fitness looks like. The easiest and most simple test to perform is the Step Test. There are many different styles, however they all test the same thing which is your aerobic fitness. All you need for a step test is a step approximately 30cm off the ground, a metronome and a timer.
Another two tests that you would have definitely heard of are the Beep Test and the Yo-Yo test. Both of these aerobic tests look at your intermittent aerobic fitness as there are slight pauses/rest periods between bouts of effort in both.
A more accurate and scientific way of determining your aerobic fitness is the VO2max test. You may have seen pictures or videos of athletes performing this test on a treadmill with a mouthpiece in that is connected to a tube. The VO2max test records how much air you are expending during exercise. The participant of the test must run continuously until fatigue while their expended air is collected in a cylinder for measurement. After running at one speed, the speed of the treadmill will increase in time increments. The VO2max test may also be performed on a bike as well.
ESSA Adults Pre-Exercise Screening Tool
It’s important to make sure that we are fit for exercise prior to starting an exercise program especially if you are returning from injury, are new to training, or may have underlying medical conditions.
“Pre-exercise screening is used to identify those who may have medical conditions that put them at a higher risk of an adverse event during physical activity/exercise. It’s a filter or ‘safety net’ to help determine if the potential benefits of exercise outweigh the risks for an individual.” – Fitness Australia
In 2010, three Australian organisations – Fitness Australia, Exercise and Sport Science Australia (ESSA) and Sports Medicine Australia (SMA) – standardised the way pre-exercise screening is undertaken in the Australian health and fitness industry.
You can find a copy of the Adult Pre-Exercise Screening Tool below:
References
2012. Developing Endurance. Human Kinetics, Inc.
Dale, P., 2019. What Does Cardiovascular Fitness Mean? | Livestrong.Com. [online] LIVESTRONG.COM. Available at: <https://www.livestrong.com/article/286610-what-does-cardiovascular-fitness-mean/> [Accessed 1 September 2020].
Fitness.org.au. n.d. Adult Pre Exercise Screening System. [online] Available at: https://fitness.org.au/articles/industry-business-support/adult-pre-exercise-screening-system/94/18/20 [Accessed 1 September 2020].
Guelfi, K., 2018. Exercise Prescription For Aerobic Fitness I.
Guelfi, K., 2018. Exercise Prescription For Aerobic Fitness II.
Marcus, J., 2013. Weight Management: Finding the Healthy Balance. Culinary Nutrition, [online] pp.431-473. Available at: <https://www.sciencedirect.com/science/article/pii/B9780123918826000108?via%3Dihub> [Accessed 1 September 2020].
McArdle, W., Katch, F. and Katch, V., 2014. Exercise Physiology. 8th ed. Philadelphia: Wolters Kluwer.
Nsca.com. 2020. Aerobic Endurance Measures And Analyses. [online] Available at: <https://www.nsca.com/education/articles/kinetic-select/aerobic-endurance-measures-and-analyses/> [Accessed 1 September 2020].
Peeling, P. and Polglaze, T., 2019. Aerobic Training.
Publishing, H., 2017. Aerobic Fitness Test: The Step Method - Harvard Health. [online] Harvard Health. Available at: <https://www.health.harvard.edu/staying-healthy/aerobic-fitness-test-the-step-method> [Accessed 1 September 2020].
Sciencedirect.com. n.d. Cardiovascular Fitness - An Overview | Sciencedirect Topics. [online] Available at: <https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/cardiovascular-fitness> [Accessed 1 September 2020].
Wood, R., 2008. Cardiovascular / Aerobic Endurance Fitness Tests. [online] Topend Sports. Available at: <https://www.topendsports.com/testing/aerobic.htm> [Accessed 1 September 2020].
www.heart.org. 2018. Endurance Exercise (Aerobic). [online] Available at: <https://www.heart.org/en/healthy-living/fitness/fitness-basics/endurance-exercise-aerobic> [Accessed 1 September 2020].