When it comes to exercise, intensity matters.
There are different ways of measuring, or gauging, heart rate intensity.
Taking your heart rate, either at the radial artery in the wrist or the carotid artery in the neck, can be dicey. Generally you need to slow down or stop to find the pulse, allowing your heart rate to drop.
Heart rate monitors can circumvent these challenges. Some exercise equipment has built in monitors and will provide a digital display of your changing heart rate. Personal heart rate monitors are also effective though are not a necessary expense. I have a heart rate monitor I haven’t used regularly in several years. Every now and then I strap it on as a check on my perceived level of work.
A common and useful test for recreational fitness enthusiasts is the talk test. If you can hold a conversation but not sing a song, you are likely working within an effective intensity level. I recall the first trainer I ever hired telling me to sing “Old MacDonald Had A Farm” when I was on the stationary bike. At the time I had no idea why and simply thought she was a bit odd, but I now understand what she was looking for.
Another method is the Rate of Perceived Exertion (RPE), sometimes referred to as the Borg Scale. The scale is meant to correspond to heart rate where the level of exertion, multiplied by 10, is roughly equivalent to the actual heart rate.
The RPE scale allows you to gauge your intensity based on how you feel. This subjective experience is based on your whole being and how you feel overall, not just that your legs are fatigued, for example. Research shows that exercisers are able to very accurately gauge and adjust their intensity based on RPE and that there is a strong correlation to heart rate.
It is also possible to set your intensity by goal. For example, if you want to run a four minute kilometre you can measure your intensity keeping that pace and then replicate the intensity level on subsequent runs.
Each method of measuring how hard you are working has its strengths. Find one with which you are comfortable, practice using it accurately, and keep yourself in a heart rate zone which will maximize your time, your energy and your outcomes!