yes and the site allows you to merge RR data from HRVLogger into a FIT file and then you can see DFA a1 at very high resolution. I am still working to understand the settings but it looks great and will work it seems for my use case. So instead of being held to one DFA a1 reading every 2 minutes you can see the DFA a1 in the range of every few seconds as well it automatically derives the aerobic threshold from the power vs DFA a1 graph. Very cool!