Heart rate is easy to forget about in this world of wearables and fitness trackers. Sure, those devices make it easier to make sure you are checking your heart rate regularly, but as I’ve previously written, it ain’t too hard to do on your own. Something you may not be getting from your fitness tracker, though, is what your heart rate range should be for a given workout. Or what you should be aiming for based on your goals. So, today, let’s do some math!

Before you stop reading because I said math, let me assure you, this is math your third grade self would be able to do. Or, you know, you can use the calculator on your phone, too. I do, so no judgement. And if you know you’ll forget later, I’ve got a handy printable that will walk you through it.

Many of us just jump on the treadmill or head out for a jog without really paying attention to what our heart rates are doing. Sure, we check the fitness tracker midway and download the info when we are done, but we don’t necessarily understand what it means. Understanding what our heart rate does in response to exercise and what our exercise ranges are can help us choose exercise intensity.

If you are training for something, even say, a 5K, certain training runs should be completed with your heart rate at a certain level. Those levels indicate the overall intensity of your workouts. If you are doing a lot of exercise at very high intensities without rest, you are placing yourself at risk for overtraining or injury.

Even if you aren’t training for something particular and are using cardiovascular exercise as part of your regular routine or to help manage weight, it is still important to have an idea of intensity. While there isn’t anything wrong with a nice walk, if that is all you’re doing and your heart rate remains at too low an intensity every single workout, then you aren’t really stressing your body enough to see changes.

Maximum Heart Rate

So, how do you calculate your exercise ranges? Well, first, you calculate your maximum heart rate. There are two ways to do this. The first method involves finding a treadmill or bike and a certified personal trainer or other health professional and then running or cycling until you literally fall down. Your heart rate when you fall down is your max.

The other safer and less embarrassing way to do this, is to use equations to estimate. Many of you may have heard of good old 220-age. This equation to predict max heart rate has been around about as long as I have. And for a quick estimate, it ain’t too bad. But research over the years has led to a new equation that the American College of Sports Medicine is touting as much more accurate. I’ll warn you, it looks scary, but it is the same basic idea as 220-age.

206.9 – (0.67 x age)

Take a breath, I promised you that your third grade self could do this. I’ll even walk you through it using my age as an example.

First, plug in your age.

206.9 – (0.67 x 38)

Then, do the part in parenthesis.

206.9 – (25.46)

Now finish the subtraction.

I get 181.44 beats per minute for my age predicted max heart rate. We’ll round that to 181 for ease of future math.

Heart Rate Ranges

Now that we have our age predicted max heart rate we can calculate our ranges. Remember that the ranges are related to intensity. The 30-50% intensity range is good for rehab conditions or active rest days. This is a very light intensity which shouldn’t tire you out. All you do is take your age predicted heart rate number from above and multiply it twice, once by 0.3 and again by 0.5 Here are my numbers…

181 x 0.3 = 54 bpm

181 x 0.5 = 90 bpm

For the record, my resting heart rate at my most fit is still about 56-58 beats per minute, so I’m already in this range just by waking up in the morning. For me, 90 beats per minute is typically my heart rate when I warm up.

The 50-70% intensity range is a moderate cardiovascular intensity. Depending on your baseline fitness and your current level of training, this could be anything from a typical walking pace to a run. This intensity level is great for general conditioning, building stamina at the start of a training program, and for managing weight. Math is similar to the first range. We already have the 50% number, so here’s the high end of the range.

181 x 0.7 = 126 bpm

For high intensity exercise, you are looking at 80-90% of your age predicted max heart rate. It should be noted that these high intensity numbers are not sustainable for long periods of time. In other words, this is the land of interval training. Intervals are amazing. They allow us to push our bodies more than we thought we could, allowing us to burn a lot of calories for weight loss or really challenge our cardiovascular systems to become stronger. Take care, though, to make sure that you can sustain moderate level exercise (i.e. heart rate of 50-70% of max) for about a half hour before you attempt anything this intense. And please make sure that you are giving yourself active rest periods. If you are doing 2-3 minute intervals at 80% intensity, you need 2-3 minutes of much lower recovery before you do another work interval. If you are at the 90% end, you need longer recovery breaks before you go hard.

181 x 0.8 = 145 bpm

181 x 0.9 = 163 bpm

So, now that you know how to take your heart rate and can calculate your intensity ranges, use that to make the most of your cardio time. If you have specific questions, hit me up in the comments or email me!

Oh, and here’s that printable I promised….

Until next time, be well friends!