Did you know that exercise intensity during a cardiovascular workout is related to your age and fitness level?

Canada’s Physical Activity Guide to Healthy Active Living tells us that the average Canadian needs 60 minutes of cardiovascular activity four times a week. However, research has found that this can be accumulated in short chunks of activity as short as 10 minutes. During this time, you need to be within your target heart rate zone.  

It’s not quite that simple. Exercising within your target heart range is dependant not only on your age but your fitness level as well as other health conditions that may be present. Generally speaking, the average person should exercise between 55 and 90 per cent of their maximum heart rate (max hr). What the heck does all that mean? It takes some basic math calculations.  Grab a pencil and paper and do this with me. 

Let’s Start with the Resting Heart Rate

Your resting heart rate is your heart rate (hr) at rest. Each time the heart pumps it forces blood to all areas of the body to meet the need for oxygen. As the demand of oxygen increases with activity the heart has to pump faster to provide more oxygen. The best time to take your resting heart rate is before rising from bed. 

With technology advances, smart watches measure your resting heart rate. This can also be done manually. Place your index and middle finger on your carotid artery (on your neck to the side of your windpipe) or your radial artery (underside of your wrist). Don’t use your thumb as it has its own pulse. Use the left side because the beat is slightly stronger as it is closer to your heart. Press gently as pressing too hard can speed up your beats per minute (bpm). Count the first beat as zero and take your heart rate for at least 30 seconds. Multiply by two to get bpm.

An average resting heart rate is 72 bpm. Typically, a women’s resting heart rate is slightly higher than a man. If your resting hr is more than 100 bpm it may be a warning sign to visit a doctor’s check up. Resting hr is relevant because as a person gets more fit their resting hr gradually decreases. 

Calculate your Maximum Heart Rate

There are a number of ways to determine exercise intensity but the most common method is using your maximum heart rate (max hr) combined with your target heart rate (target hr). 

The max hr is used to evaluate how hard the body is working when completing cardiovascular activity. 

The calculation is 220 – age = max hr

There is a linear relationship between exercise intensity and the hr response. In general, when exercise becomes more difficult, your body adapts by increasing hr to increase oxygen supply and extraction. 

As we age, our hr slows down and has reduced capacity. Knowing your max hr allows you exercise at safe level.

Let’s take an example of a 45-year-old. Subtract their age of 45 from 220 to get a max hr of 175. This will help you understand that the max hr of a teenager will be higher than an older adult. 

Calculating your Target Rate Training Zone

It is recommended that you work in a target training zone (target hr) between 55 to 90 per cent of your max hr. A person with a very low fitness level should exercise at 55 per cent of their max hr in comparison to an athlete with an above average fitness who could safely work as high as 90 per cent of their max hr. From my perspective as a trainer, not many people should work at 90 per cent. I recommend going no higher than 85 per cent.

With that information in mind, target hr ranges can be adjusted between 55-90 percent of your max hr. 

Let’s use the 45-year-old with an average fitness level and use 65-74 per cent of the max hr.

max hr 175 x 65 per cent = 113

max hr 175 x 74 per cent = 129

The optimum cardiovascular exercise range for this 45-year-old is between 113-129. This range changes dependant on level of fitness. This is where a trainer can be beneficial in ensuring the correct level of fitness for individuals with different variables. 

With your target hr range, you can monitor your exercise levels with a heart rate monitor, smart watch or you familiarize yourself with using the perceived exertion scale. 

Perceived Exertion Scale – developed by Dr. G Borg

Dr. Gunnar Borg developed the Perceived Exertion Scale from six to 20 with six being extremely light and 20 being maximal exertion. The scale has been modified to make it easier to monitor exercise intensity using a one to 10 scale where one is very light activity and 10 is maximum effort. 

In summary, exercise intensity has many variables and is impacted by health conditions. Always consult a doctor before beginning an exercise program. 

Today is your day get moving. 

About Kimberly Hicks-Ruttan

Hi, I’m the founder of Fit2Move - virtual fitness in your home, on your own time. I am a certified fitness instructor and personal trainer. Connect with me on Facebook where I run a FREE group called Fit Tips with Kimberly.