Heart rate training zones are calculated by taking into consideration your Maximum Heart Rate (HRmax) and your Resting Heart Rate (HRrest). Within each training zone, subtle physiological effects take place to enhance your fitness.
The Energy Efficient or Recovery Zone – 60% to 70%
Training within this zone develops endurance and aerobic capacity. All recovery running should be completed at a maximum of 70%. Another advantage of 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-energize 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 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 Zone – 80% to 90%
Training in this zone will develop your lactic acid system. In this zone, your anaerobic threshold (AT) is found – sometimes referred to the point of deflection (POD). During these heart rates, the amount of fat being utilized as the primary 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 can no longer 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 time or by pushing the AT higher.
The Red Line Zone 90% to 100%
Training in this zone will only be possible for short periods. It effectively trains your fast-twitch muscle fibers and helps to develop speed. This zone is reserved for interval running, and only the very fit can train effectively within this zone.
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 several 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 acclimatized
• Biological variation can mean the heart rate varies from day to day by 2 to 4 beats/minute
Resting Heart Rate
To determine your resting heart rate (HRrest) is very easy. Find somewhere nice and quiet, lie down, and relax. Position a watch or clock where you can see it while lying down. After 20 minutes, determine your resting pulse rate (beats/min). Use this value as your (HRrest).
If you have a heart rate monitor, then put it on before you lie down. After the 20 minutes, check the recordings and identify the lowest value achieved. Use this value as your HRrest.
The heart is a muscle, so with regular exercise, it will become larger and become more efficient as a pump. As a result, you will find your resting heart rate gets lower so you will need to check your HRrest regularly (e.g. Monthly).
Calculation of a zone value
The calculation of a zone value, X%, is performed in the following way:
• Subtract your HRrest from your HRmax giving us your reserve heart rate (HRreserve)
• Calculate the required X% on the HRreserve giving us “Z”
• Add “Z” and your HRrest together to give us the final value
Example: The athlete’s HRmax is 180, and their HRrest is 60 – determine the 70% value
• HRmax – HRrest = 180 – 60 = 120
• 70% of 120 = 84
• 84 + HRrest = 84 + 60 = 144 bpm
MACKENZIE, B. (1997) Heart Rate Training Zones [WWW] Available from: https://www.brianmac.co.uk/hrm1.htm [Accessed 19/7/2020]