On sunday I did one hour ice skating at the Vechtsebanen in my hometown Utrecht. Heartrate average 140, peak 164, Suunto T4 trainings effect (T.E.) 3.9
The nice thing about ice skating for me is that I can control my heartrate better than with cycling or rowing. When my heartrate is up to about 155 bpm it still feels quite relaxed and it seems like I can continue for a long time. I was very much overdressed and sweating a lot! It occurred to me that sweating at cardio is what contractions are for freediving. It's not very nice, irritating at times maybe but also not to bad in the end.