I'm guessing Open Water Swimming (OWS) might be best as it's the only activity configured to cope with the periodic submersion in water and consequential drop in GPS signal.
I used to use a simple sports watch to know how many calories I was burning. Recently, I don't use them, as I'm in good shape and everything I eat is burned in one workout. If you exercise daily, then counting calories or tracking activity is a waste of time. I had a period of time when I didn't exercise and gained a lot of weight even though I was counting calories. When I saw my figure in the mirror, I immediately decided to order a surfboard on https://outdoorlifecafe.com and resume trainings. During this period of my life, I realized that the main thing is sports.
