The intensity of your workout will determine how much oxygen the working muscles require to maintain function during this time. The following information explains some key physiological differences between exercise intensities that most clients will have experienced in their training.
Heart rate training zones are calculated by taking into consideration your Maximum Heart Rate (MHR). Within each training zone, subtle physiological effects take place to enhance your fitness. MHR is calculated by subtracting your age from 220BPM (unless an underlying heart issue exists). A heart rate monitor is the ideal tool to keep track of your heart rate during exercise, and these are available at your Optimum studio.
The Energy Efficient or Recovery Zone – 60% to 70%
Training within this zone develops basic endurance and aerobic capacity. All easy recovery running should be completed at a maximum of 70%. Another advantage to running in this zone is that while you are happily fat burning you may lose weight and you will be allowing your muscles to re-energise with glycogen, which has been expended during those faster paced workouts.
The Aerobic Zone – 70% to 80%
Training in this zone will develop your cardiovascular system. The body’s ability to transport oxygen to, and carbon dioxide away from, the working muscles can then be developed and improved. As you become fitter and stronger from training in this zone it will be possible to run some of your long weekend runs at up to 75%, so getting the benefits of some fat burning and improved aerobic capacity.
The Anaerobic (oxygen free) Zone – 80% to 90%
Training in this zone will develop your lactic acid system. In this zone, your individual anaerobic threshold (AT) is found. During these heart rates, the amount of fat being utilised as the main source of energy is greatly reduced and glycogen stored in the muscle is predominantly used. One of the by-products of burning this glycogen is lactic acid. There is a point at which the body cannot remove the lactic acid from the working muscles quickly enough. This is your anaerobic threshold (AT). Through the correct training, it is possible to delay the AT by being able to increase your ability to deal with the lactic acid for a longer period of time or by pushing the AT higher.
Training above 90% of maximum heart rate is achievable, but only for short amounts of time (~15 seconds) and generally is an intensity reserved for elite athletes.
Heart rate variations for a given intensity
A reduction in heart rate for a given intensity is usually due to an improvement in fitness but a number of other factors might explain why heart rates can vary for a given intensity:
- Dehydration can increase the heart rate by up to 7.5%
- Heat and humidity can increase the heart rate by 10 beats/minute
- Altitude can increase the heart rate by 10 to 20%, even when acclimatised
- Biological variation can mean the heart rate varies from day to day by 2 to 4 beats/minute.
Understanding these principles will allow you to continue to achieve positive results, especially in your home cardio programs. It is advised that you purchase a heart rate monitor so that you can be sure to work within the heart rate zones you are targeting and therefore be working the desired energy systems.