Aerobic Training Considerations
What is referred to as cardiovascular health is really the ability to utilize oxygen efficiently throughout multiple systems. That is the moment you take a breath in, how efficiently your diaphragm and accessory muscles work to bring in a desired volume of air, to blood flow from the lungs to the heart and the entire vascular system, down to muscle and the mitochondria in each individual muscle cell. For simplicity, this is what the cardiovascular system is referring to in the following text.
The ability to do what is mentioned above declines with age. Intense exercise on the other hand can improve cardiovascular health, reduce or eliminate diabetes, reduce the risk of cancer, prevent cardiovascular disease. To move is to live.
Traditionally moderate intensity aerobic exercise 30 minutes a day 5 days a week is what is recommended by the American Heart Association and the American College of Sports Medicine. But, in reality, this may still not be enough. HIIT on the other hand is safe in all levels of athletes when applied correctly. The time demand is far less and can be done in as little as 14 minutes 3-4 days per week. Here is a handy reference known as the Modified Coggan Power Scale. HIIT training levels start in zone 4 and go up to zone 7. This is important to design a program.
Designing an aerobic program has a number of variables to consider. An exercise mode for example. Boxing or running? Bicycling or swimming? Etc. But also training frequency, exercise duration, and training intensity.
One can take the moderate intensity over longer time frames approach to training, but most data available for its usefulness came from studying elite athletes. In addition to the 30 min/day 5 days per week above the ACSM recommends adding in resistance training, flexibility training, and balance exercises 2 days per week. This lacks detail and may not be ideal, but it does cover the different areas needed to maintain independence in daily living activities.
Don’t confuse HIIT training with high volume training. High volume training is more likely to lead to injuries and is often cited incorrectly when discussing HIIT training. How does one take an aerobic activity they love to do and design a HIIT program? Start by calculating maximum heart rate. A VO2 max study can do this and is considered the gold standard, but few have access. Use the following formula to calculate maximum heart rate.
220-AGE = the Age predicted maximum HR (APMHR). Take the maximum HR calculated and subtract the resting heart rate. This is the Heart rate range (HRR). Then calculate the Target HR by multiplying HRR with percent of exercise intensity desired from the modified Coggan Power Scale and add that to your RHR. For example, if you are 40 with a resting heart rate of 70. The APMHR is 220-40 = 180. The HRR is 180-70 = 110. THR = 110*.9+ 70 = 169. This is the Target HR for beginning HIIT training in this individual.
There are three main intervals to train in terms of muscle metabolism. Slow glycolytic metabolism or aerobic in the 1.5-3 minute range, fast glycolytic metabolism or anaerobic in the 0/5-1.5 minute range and for phosphocreatine metabolism at <30 seconds. It is generally recommended a work to rest ratio of 1:9 or 1:8. For example, if someone does 1 minute sprints on bike, 9 minutes of rest should be done prior to doing another work set. 4-6 cycles are typical to complete training and have been shown to improve cardiovascular health over time. To compare to traditional aerobic training, workouts greater than 45 minutes would have to done to be comparable of 20 min of HIIT training. HIIT training has shown to improve VO2 max, lipid metabolism, mitochondrial activity, lactate buffering by muscle cells and muscle glycogen content stored for energy. In addition, HIIT training reduces mortality.
HIIT training also has been shown to have benefits with those that cross-train, which is to add resistance training to their regimen. HIIT training as not been shown to decrease power where endurance aerobic training has. Although it should be noted in these studies the aerobic and resistance training were done on alternating training days.
Some types of HIIT training include sprinting (running, cycling, swimming, rowing etc.) boxing, and weightlifting with little rest in between sets.