I review sports watches for a living and this free Garmin app makes heart rate training more fun

Using your heart rate is a great way to judge your effort during training, whether that’s to ensure that you’re not pushing too hard during easy runs or pushing hard enough during HIIT workouts in the gym.

I’m a keen runner and always keep an eye on my heart rate during runs, just to make sure it’s in roughly the right place for the effort I feel I’m putting in — sometimes a strangely high reading is a sign I’m getting ill, for example.

Naturally, you can just use your actual heart rate for this, using the heart rate zones on your watch and getting to know the bpm you usually work at. Or, if you use one of the best Garmin watches, you can make things more fun by installing the free Garmin Connect IQ app Pulse OX, which allows you to assign a different animal to each heart rate zone.

Pulse Ox is free and fun to use

It’s not the most sophisticated Garmin Connect IQ app out there, but Pulse OX is free and easy to install and set up.

Once you’ve found it in the Connect IQ store, you install it to your watch and then assign it to a data field in your sports modes. For example, in the running mode on my Garmin Fenix 8, I have it set up on a simple screen along with workout duration, for when I’m just running to time and heart rate.

Then you go into the Pulse Ox settings in the Connect IQ app and pick which animal you want for each zone — there are 22 zones available, so you can really customize this to your heart's content.

You actually don’t have to pick an animal at all — you just type what you want to show for each heart rate zone, and it’ll show during workouts, but animals are more fun, I think.

For my purposes, I just use seven of the zones, with a huge zone 1 that I’ve named after my incredibly lazy cat Taz, then I progress through various animals (mostly cats, I like cats) up to Cheetah for my max heart rate zone.

Then you head out and train, and suddenly, pushing to a high heart rate zone feels a little bit more fun. Maybe.

How to get your heart rate zones right

To use this app or do any kind of heart rate training, it’s important to know your heart rate zones. These will be set up by default on sports watches, but based on population-level estimates that might not be correct for you.

The standard estimate used subtracts your age from 220 to get your max heart rate, then zones are worked out from there.

However, for me, this would mean a max heart rate of 184bpm, when mine is actually more like 174bpm, so my zones would be completely off.

The best sports watches do adjust your max heart rate and zones automatically using data from workouts over time, but it’s still not always reliable.

You can find your true max heart rate by looking at the measurements from a watch or heart rate chest strap during your hardest workouts, or something like an all-out 5K race if you’re a runner.

Then use this max heart rate to work out your rough training zones. There are a lot of models out there, but a basic one would be 60-70% of max heart rate is your easy training zone, 70-80% is for aerobic endurance, 80-90% is for hard intervals, while 90% and above is flat out.

Just bear in mind that the optical heart rate sensors on smartwatches are not always reliable — I myself use a chest strap monitor for more accurate heart rate measurements during workouts.

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