Tag Archives: Heart Rate

Opening Suunto *.sml files with KubiosHRV

As you can read in my description, I am both a Software engineer and an endurance athlete. This combination results in the fact that I enjoy gathering and analyzing data of all my athletic endeavors.

For most of my activities, I use a GPS watch combined with a heart rate belt to ensure I train and race at the correct intensity. One of the many benefits of tracking heart rate data is the ability to analyze Heart Rate Variability (referred here as HRV) in order to avoid over-training. If you have never heard of it or if you would like to know more about it, I recommend the following article.

Ambit2Suunto Ambit2

The watch I use, a Suunto Ambit 2, allows me to record the R-R data (R-R is a synonym of HRV). Analyzed, this data can quickly tell me if I’m over-trained or not.

My protocol has been to measure my resting heart rate in bed when waking up. I measured it over a period of time, usually when I was peaking for a race. While Movescount (official Suunto website associated to any Suunto Device) allows anyone to see its R-R data for a given activity, it doesn’t offer a way to analyze the data. Who knows why?

RRMovescount It doesn’t look like I’m overtrained since it doesn’t look like anything!

Analyzing any R-R data is actually quite complicated and requires some very advanced mathematics (Digital Signal Processing algorithms). For this, I use a free software called KubiosHRV. You can find a great video tutorial on how to use this software here.

kubioshrvreport Example of KubiosHRV report

While KubiosHRV offers a quick & accurate way to analyze one’s HRV data, it can’t directly open a Suunto *.sml file (the Suunto ambit file format since 08/2014) to analyze the HRV data.

KubiosErrorError while opening a Suunto SML file

After playing around with Kubios, I found a way to fix this issue but it requires to modify by hand each SML file that you want to analyze.

I created a small tool to do this in batch: KubiosHRVDataFormatter (Download here 03/01/2017 UPDATE V2.0 AVAILABLE) will allow you to convert easily a given batch of Suunto SML files into a corresponding batch of xml files directly readable by KubiosHRV.



=> Open KubiosRVDataFormatter

=> Select the Suunto *.sml file(s) that you would like to convert

=> Specify the directory where you would like to have the converted Suunto files created

=> Open Kubios HRV and load your HRV data!



Let me know if you have any questions about the tool. As of today, it will only format the Suunto *.sml files but if you encounter the same issue with other file types, let me know and I can enhance the tool to convert them as well.

Notes: KubiosRVDataFormatter is compatible with Windows 7/8/8.1/10