What should my heart rate be when exercising?

With the emergence of activity trackers such as the Fitbit, people have more and more access to information about their health. One of the more common questions that we get when people start an exercise program is what their heart rate should be. 

Unfortunately the answer to this question is not a simple one. Like most answers, it depends on a few different factors. The first of these is the type of exercise. In general, aerobic training -such as walking- if done in its traditional way (similar pace for a long period of time) should see the heart rate rise to a point that is around 60-70% of your maximum heart rate and hover around this value for the duration of your exercise. More recent changes in the way people train aerobic fitness such as interval training (short bursts of higher intensity exercise interspersed with active recovery) will cause the heart rate to rise up beyond this temporarily while intensity is at its peak and then return to a lower value when in active recovery. If you look at the whole period of interval based exercise, heart rate should have a fairly consistent pattern allowing you to easily identify the peaks in intensity.Strength training on the other hand is a different story. Heart rate will be much more variable and doesn’t always return back to a predictable value during recovery. 

Another consideration is the level of physical condition of the participant. People who have been regularly exercising have a lower resting heart rate and often lower values when doing exercise as their body becomes more efficient. On the flip side they can often exercise at higher intensities because of this and may find that they can maintain exercise at a higher intensity and subsequent heart rate.

Finally medical conditions and medications can significantly affect heart rates. People who are on heart medications like beta blockers or who have a pace maker installed often have different heart rate reactions.

So what should maximum heart rate be? The answer to this question based off some questionable studies in the 1970s is 220-age. However more recent research into this shows that a better formula is 208  – 0.7 x age. Even still this value is only a rough average with 1 in every 3 people more than 10 beats off this value.

With this in mind a better way to tell if you are exercising at the right intensity is to use a scale rather than your heart rate. The scale most commonly used by exercise physiologists is called the “rate of perceived exertion” and asks you on a scale of 1-10 (or sometimes 6-20) how difficult the exercise is with 10 being absolutely exhausting!