You don’t know what you don’t know. When you begin an exercise or training program, you might find that your cardiovascular system has a hard time keeping up. Low cardiovascular endurance can look like shortness of breath, light-headedness and dizziness, or nausea and fatigue.
All exercise modalities fall under either aerobic or anaerobic. Aerobic exercise uses oxygen for fueling muscle fibers. Anaerobic muscle contractions are fueled by energy sources stored in the body and are not dependent on the oxygen we breathe. Aerobic exercise is of a lower intensity and a long duration, whereas anaerobic exercise is shorter and of a higher intensity. In order to fuel these different types of activity, our body runs three different energy systems.
The first system, the creatine-phosphogen system, engages first and covers roughly the first 10 seconds of intense activity. It is anaerobic in nature. The second energy system to engage, glycolysis, is also anaerobic and covers roughly the first 3 minutes of activity. Finally the oxidative system allows you to go beyond 3 minutes of work and is aerobic in nature.
So what does that mean, and how can you use that information to help train your cardiovascular system? Although all 3 of these systems overlap, and most training based activity stresses each energy system in some way, you must manipulate two variables to tax a specific system: work to rest intervals and intensity. The more intense the exercise, the longer the recovery needs to be. Makes sense, right? Check out this chart for optimal work to rest ratios:
Targeting the Three Primary Energy Systems
Interval training targets all three primary energy systems: creatine phosphate, aerobic and lactic acid.
Aerobic Ratio
Ratio: the aerobic ratio is: 1:1 to 1:0.5. Start at the highest ratio (1:1) and over time progress on to the harder ratio (1:0.5)This equates to: four minutes of work followed by four minutes of rest, repeat x desired number of reps. Or 4 minutes work followed by 2 mins rest, repeat x desired reps.
Minimum work duration: to ensure that the energy system used is aerobic and not lactic acid, the minimum work duration should be two minutes.
Maximum work duration: depends on the individual’s goals.
If training for a marathon, they might carry out 1 or 2 mile intervals. These could be four-minute miles to 15-minute miles, depending on their ability and fitness levels. For recreational use, a two-minute interval would be more appropriate.
Lactic Acid Ratio
Ratio: the lactic acid ratio is: 1:4, 1:3 or 1:2. Start on the highest ratio (1:4) and progress down the ratio’s as your lactic acid tolerance and lactic acid removal pathways improve. This equates to: one minute of work followed by a four-minute rest; or 30 seconds of work followed by a 90-second rest; or 30 seconds of work followed by a 60-second rest.
Repeat each protocol for the desired number of reps.
Minimum work duration: 15 seconds, in order to promote the use of the lactic acid system rather than the ATP/CP system (creatine phosphate).
Maximum work duration: this varies depending on fitness level and lactic acid tolerance. For example, a highly trained athlete can maintain a higher output for longer, resulting in higher lactic acid levels.
Generally, you won’t be able to maintain a high (lactic acid generating) output for longer than 2-3 minutes.
Creatine phosphate (ATP/CP) ratios
Ratio: 1:6 or higher, up to 1:50 (or higher)This equates to: 10 seconds of work followed by 60 seconds of rest, or even five seconds of work followed by 250 seconds (4 mins 10 seconds) recovery.
Minimum and maximum work duration: this depends on the type of explosive fitness required by each individual. For example, Usain Bolt requires a large ratio to ensure that every time he works, he is training as fast as possible with no fatigue. Whereas an everyday gym-goer may be happy to work on a rower for 10 seconds, followed by 60 seconds of rest, to help develop their energy system.
With the right work to rest ratios and intensity, your cardiovascular system will improve in no time. If you’d like to learn more and schedule a complimentary training session, please send contact us.
