How to measure heart rate reserve and training zones

If you are into fitness and go to a gym or aerobic fitness centers you might have heard about the terms like heart rate reserve, target heart rate and training zones.

These terms might seem confusing but they are actually easy to understand and knowing them is very important if you want to lose weight or want to improve your overall cardiovascular fitness. Let’s dive in and try to understand each term.

Resting Heart Rate (RHR)

This is your general heart rate when your body is completely relaxed. You can calculate resting heart rate by taking readings of your pulse in the morning when your body is completely relaxed. To measure over your radial artery and count the number of pulses/beats in one minute. Repeat this process for at least 3 days to get a better reading.

RHR = (Day 1 RHR + Day 2 RHR + Day 3 RHR) / 3

A normal resting heart rate for an average adult is between 60 to 100 beats a minute. As your level of fitness improves, your resting heart rate goes down. Most highly conditioned athletes have heart rates of 40-45 beats per minute.

A lower resting heart rate in this range implies better cardiovascular fitness.

Maximum Heart Rate (MHR)

MHR is the upper limit of physical exertion that your cardiovascular system can. This is generally estimated by deducting your age from the number 220.

Maximum heart rate declines as you age.

Target Heart Rate (THR)

Target Heart rate is defined as the number of heartbeats required to reach the level of physical exertion vital for cardiovascular fitness specific to age, gender and physical fitness of a person.

Heart Rate Reserve (HRR)

Heart rate reserve is defined as the difference between your maximum heart rate (MHR) and resting heart rate (RHR).


Target Heart Rate Training Zones

Target heart rate training zone is defined as upper and lower limits of physical training intensities. It is calculated using Karvonen Formula and is expressed as a percentage of maximum heart rate.

Karvonen Training Heart Rate = % Training Intensity (HRR) + RHR

Based on the Karvonen below is a rough guide to training heart rate zones

Recovery Zone (50% – 60%)

This is the lowest intensity zone with the goal to improve cardiovascular fitness by subjecting your body to little stress. The focus in this zone is on body warm-ups and doing recovery between high-intensity training. Workout for 20 minutes in this Zone. At this intensity, you should be able to breathe and talk easily.

Aerobic Zone (60% – 70%)

Training in this zone improves your endurance and aerobic fitness by subjecting the body to moderate stress. Workout for 30 minutes in this Zone. You will have to make a little effort to breathe and talk.

Stamina Zone (70% – 80%)

This is a moderate intensity zone. Exercising in this zone will help to develop your aerobic system and in particular your ability to transport and utilize. Working out in this zone helps you sustain your fitness form over longer durations. There will be a spike in your breathing rate and you will have some difficulty in talking.

Anaerobic Threshold Zone (80% – 90%)

This is high-intensity zone at which your body is consuming oxygen at the highest rate. Training in this zone increases your body’s ability to use oxygen to produce energy. Exercising at this intensity is usually done to improve athletic performance. It is not recommended for weight loss.

Anaerobic Zone (> 90%)

Training in this zone increases your body’s ability to generate muscle energy without oxygen.