Back in April this year (2014) I wrote about how it was possible to get HR underwater using ANT+ and a MIO Link optical HR Wrist strap. Things have moved on a bit since then with more optical HR options and new sports watches from Garmin (920XT), Suunto (Ambit3) and Polar (V800).
As I write this towards the end of October 2014 there is still no easy way to properly and ubiquitously get underwater HR data. But there are several workarounds and near-solutions.
It is possible to get HR Data Underwater AND merge it with a Garmin Pool swim activity.
NOTE: This document is not yet complete and fully checked. I need to clarify some of the details and add some bits that I know are currently missing. However it’s good as a general guide for you now.
We need to first look at sensing and transmitting the HR Data.
1. Legacy Polar
Even the ancient Polar watches were able to record HR underwater. They used a signal that went MUCH further through water that ANT+ or Bluetooth.
I’m not sure exactly why Polar moved away from this, probably: to use more standard protocols; to use protocols that can uniquely pair devices; and to use more energy efficient methods.
2. Chest Straps vs Optical HR Wrist Monitors
Chest straps are probably the best and most accurate way of sensing electrical impulses in the chest and then broadcasting the beats to whatever is listening. However, if the strap broadcasts using either Bluetooth or ANT+, then the signal will only travel a very few centimeters ie NEVER to the watch on your wrist.
So then we have devices like the MIO Link which record data optically and then transmit via ANT+, Bluetooth or both/either. If that wrist monitor is sufficiently close to your watch (on the same wrist) then your IS able to receive a HR signal.
Newer optical HR sensors on the wrist are great. Especially devices like the TomTom MultiSport Cardio where everything is on your wrist in one unit. They might want to enable HR recording from swimming…
However. Optical sensors shine a light onto your skin and measure it bouncing back. If water gets between your skin and wrist strap then the readings can be way out. Having said that, I’ve also had good success with this method.
So. Optical HR is a reasonable way forwards but maybe not perfect.
In comes Suunto and Wahoo.
The Suunto Smart Strap (for the Ambit3, using Movescount) and the Wahoo TICKR-X (for generic ANT+ and Bluetooth devices, using WAHOO FITNESS) both use a conventional chest strap BUT their HR pods have a memory that is able to store HR data. In the case of the TICKR-X a whopping 14 hours…more than enough.
At the end of your session, or during pauses in your session (Suunto) the strap synchronises with a smartphone app. This could be at the end of your lane, the car park at the edge of a lake or at home. Sorted.
Surely then this ‘caching’ is the way forwards?
Well, maybe. The catches are that, firstly, a HR strap doesn’t look great when you are in a pool. OK you might have it under a swimsuit or wetsuit. But many guys will not want to wear one in the pool. There are further problems as, secondly, even a half-strong push off from the end of your lane can dislodge even the tightest of chest straps. Still women are OK and everyone is fine in the sea or in a lake with their wetsuit on.
Thirdly you still have to get the darned data back to your sports data analysis tool of choice – be it Garmin Connect, Training Peaks or SportTracks.
3. Getting the data where you want it.
Well I want it in SportTracks. You might well want it in Training Peaks. Newbie triathlete Jo Doe may well be happy to keep it in the Wahoo fitness app. Many Garmin devotees will go for the ever-improving Garmin Connect. The issue is that there are tens of thousands of us who want our data in different places compounded by manufacturers who want to ring-fence and monopolise their particular product set.
Well if you are a Suunto user then you are already sorted. You have the data in the Movescount environment. You’ve nothing more to do.
Similarly with the Polar V800, it records HR underwater. However the analytics are not yet there …
Let’s say you want the data in TrainingPeaks. Well if you have the pro edition then you could quite readily use Tapiriik.com to synchronise with dropbox, SportTracks and Garmin Connect. Oh hang on a minute none of those include WAHOO Fitness or Movescount. Well if you put it in Strava then you should be good to go. You can connect Moevscount with Strava and then Tapiriik will sync Strava with all the above.
And therefore if you are a Garmin Connect or SportTracks user then this method is also fine.
If you are a Garmin user then the situation is a bit different.
For starters, in openwater swim mode, the 920XT records HR data from a wrist based ANT+ strap. Sorted. But if you have a 910XT or indeed any other Garmin model you are NOT sorted. Neither are you sorted in pool mode on the 920XT, although it is possible this might be enabled in future firmware releases.
With the 910XT, or indeed any other Garmin, you can only record HR data underwater if you set it to, say, run mode where it will record HR but then you will not get any of the swim metrics supported by your watch. Dilema.
So the solution here seems to be to use one of the chest straps that store data and upload the information in a second/parallel exercise file. And here is where the Suunto (Movesount-Strava-Tapiriik) or WAHOO FITNESS (Garmin Connect, iOS only) comes in.
However you are still left with two activities.
I believe you cannot merge them in any of SportTracks/TrainingPeaks or Garmin Connect.
However there is a 3rd way
4. Combining The Data How You Want It
As I said previously, with the Suunto Ambit3 and Smart Belt and with the Garmin 920XT you are either OK now or probably will be soon in the case of the 920XT.
My suggestion for the 910XT and 310XT is to use the WAHOO TICKR-X alongside using the watch how you normally would (but obviously without the HR).
When you have finished your swim set the WAHOO FITNESS app can trim the data to get rid of unwanted bits at the start and end of your session. You can then export to a TCX file. If you manually import that TCX file into SportTracks (having already imported your regular pool activity) then SportTracks will allow you to add the HR track to that activity.
However. It’s a bit longwinded as now you can automatically sync your PC SportTracks with SportTracks Mobi (requires a paid for account), tapiriik (requires an annual contribution for automation) and the paid for version of Training Peaks and Garmin Connect.
and, no, I haven’t tested every possible combinations of software and linking them !! And I don’t intend to.
In the PC version of SportTracks with the POOL plugin (excellent) the developer, mechgt, has yet to show HR. So you cannot see how it varies for the different components of your pool session (yet).
Why do you actually want HR data from swimming? I use it to measure my overall training load. That’s all. So I only have to do it properly once every few months to make sure my estimate of TRIMPs per length is up to date.
If you want to look at HR data while you are swimming (you are mad).
If you want to look at average HR for your last set. That’s reasonable. You could just get out of the pool and check your HR or use one of the belts that cache your HR..
Would I go through that synchronisation malarkey 3 or 4 times a week. Err…no! But at least now you know how it can be done.