As to heart rate, watch the sweepers after a run to see how much they have exerted themselves. When sweeping they are supporting their weight on that broom while sweeping . Tough workout.
A tough workout? Really? It's only around 10 secs of brushing. Most of the heart rate is from their excitement. If they're out of breath after 10 secs…
I do understand the scoring and strategeries, I mentioned that. That's not what I'm talking about though. My point is that it may be called a sport, but I don't consider the participants anywhere near the same caliber of athletes as compared to any of the other events in the Olympics. I don't get how it became an event. All of the other sports require a combination of amazing stamina, precision, strength, coordination, dexterity, and nerve, and except for Ski Jumping, many times more than 10 seconds of physical activity. Although comparing the level of precision, strength, coordination, dexterity, and nerve required for Ski Jumping to Curling, they are worlds apart.
Watching any of the other events can be compelling and breathtaking. Sorry, Curling just doesn't do it for me like the rest. Like horseshoes and billiards, it seems like a great drinking sport.
Horseshoes has more action though.
Look at pictures of the sport from way back, pre-Olympic days. It's a bunch of men in overcoats, boots, and hats, many of them older men too. A bit different class of "athlete" as compared to any other sport.
Anyway, like has been mentioned, the whole thing used to be about amateur athletes competing. They're all professionals now. I really haven't watched much of any of it this year.