Saturday, 6 April 2013

Working out your target heart rate

I'm not even going to apologise for not being here for a very long time. It's pretty much taken as read that each post will be a long time after the last.

As you can see from my last post, I signed up for a fantastic blogging challenge where you post every day of April (barring Sundays) and each post corresponds to the next letter of the alphabet - 26 letters, 26 days. I signed up, then unsigned, but not before I'd decided on what my posts would be about, so I'm going to (yes, sporadically) post them.

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I originally wrote a different post for today, but then I realised this needed to be slotted in first. I apologise for the amount of maths involved!

This is the original way to work out your target heart rate. I'll assume that I want to work out at 70% of my maximum heart rate (max HR)

220 - age = max HR
maxHR x 70% = target heart rate

So, inserting my info: 220 - 39 = 181
181 x 70% = 126 beats per minute (bpm)

For a couple of years now, in my gym, we've been using a different formula. For this you need to know your resting heart rate, which is easily worked out by counting the number of beats in a minute - that's it. The best time to do it is when you've been sitting still for a while and not while drinking coffee and watching horror films. Being as calm as possible will give you the most accurate count. Alternatively, there are a couple of phone apps which will do it for you.

The formula looks like this:
200 - (age x 0.5) = max HR
(maxHR - resting HR) x 70% + resting HR = target heart rate

And with my info: 200 - 19.5 = 180.5
(180.5 - 54)  x 70% + 54 = 142 bpm

So you can obviously see the difference between 126 and 142. Knowing my own training, at 126 bpm I'm barely breaking into a sweat. I could easily do that all day and it would probably make no difference to my fitness because I'm firmly within my abilities. At 142 bpm I am starting to feel a little more breathless - it's still quite easy, because I've been training for 15 years, but I'd definitely feel like I was working out.

Because my body is used to cardio, I tend to workout at 85% of my max HR. So next time (which will be quite soon, because it's already written) I'll explain the basic differences between intensity levels.


  1. I love playing with my heart rate on the equipment, getting to a certain point and sustaining that or working at intervals. The awareness of what's going on with my HR as I work out increases my endurance. Great article-- and no matter how frequently or infrequently you get to this blog-- it's all good. I love visiting when you post something.

    1. Thanks for reading Julie! Sustaining those high heart rate levels is a fantastic workout - I love doing that as well!