Feedback From Heart Rate On Your Swim Training

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Feedback From Heart Rate On Your Swim Training

Many of the wearables on the market such as the new Garmin Swim 2 and Apple Watch can now measure your heart rate when you swim without the need for a chest strap. But how should you use this data to best effect?

As you probably know, at Swim Smooth we have pioneered controlling the intensity of your swimming during key training sets using Finis Tempo Trainer Pros. By knowing your CSS pace you can program a precise time per lap into the Tempo Trainer and so very accurately control how hard you are working from your first lap to last.

Heart rate on the other hand gives an insight into your physiological resonse to training. It gives a delayed reaction to intensity and is influenced by many other factors such as fatigue, hydration levels and water temperature. For that reason it's not a great way to control your intensity but it can offer a lot of insight in other ways.

Here's two heart rate traces from Sean who swims in the SS squads in Perth. Each is a complete CSS session including a warmup and some drills before the main set.

During the first session Sean led his lane. He averaged 1:27 /100m pace during the main set, hitting 176BPM towards the end. You can see a nice consistent build in heart rate through the main set indicating a strong aerobic load which is great training for distance swimming.

Sean then repeated the exact same session but this time drafted behind some slightly faster swimmers than himself:

This time he was faster, averaging 1:25 /100m in the main set but you can see his heart rate doesn't have the same consistent build and he achieves a lower 161 BPM maximum.

So having heart rate recorded during this swim allowed Sean to understand that although he swam faster drafting in the group during the second swim he actually had a poorer session from a training point of view with less aerobic load. Many swimmers would fall into the trap of thinking the opposite, that swimming faster means a better performance and therefore better training.

Here's another example of SS Head Coach Paul Newsome swimming a CSS session on Thursday night here in Perth:

Paul's an experienced swimmer and you can again see that "solid block" of building heart rate through the main set. Myffy (Swim Smooth's new community manager) swam the exact same session at the same time:

And you can see how inconsistent her heart rate was, dropping right down as she stopped during the main set several times. Myffy is new to swimming and setting off a little too quick caused her to need to stop for additional rest, harming the quality of her training. With the insight of the heart rate data she'll take this on board and improve on things next time around.

There are lots of influences on heart rate which make it a challenging metric to interpret at any given moment in time. For that reason it's tempting to disregard it completely, however looking at the trends in your heart rate over the course of a key training set can clearly show when you executed a good session and maintained a good aerobic load.

A key take away here for your own training (regardless of whether you monitor your heart rate) is to make sure that you design sessions with short recoveries and stick to them. It's easy to chat to a friend or slip in a little extra rest during a main set but as we can see above this harms the quality of the session. This is especially important for CSS and Red Mist sessions where it's all about aerobic load.


Swim Smooth!