Swim V Bike V Run Heart Rates

Hey all,
I know from experience and have read many times that swim HR is about 5-10 beats on avg lower than bike, which in turn is 5-10 beats lower than running on avg.

I read that this was due to the position our bodies are in for each discipline i.e. lying, seating or standing.

I've also been told that you use more muscles running than bikeing which use more than swimming and this is why the HR are so different.

Which of these theories is correct?

Surely when you're swimming you're using alot more muscles than cycling. Cycling is just legs but swimming is legs and arms! Can anyone clarify the Swim V Bike V Run HR issue for me.

Thanks
tribetter

Prob a bit of both really. Stand up and check your pulse. Then Sit down, then lie down. It's easier for the heart to pump blood when you are lying down, so that will be the lowest of the 3 heart rates.

Running is hardest as you support your weight and use more muscles, and your heart pumps against gravity.

Cycling - mainly your legs, but you aren't horizontal.

Swimming - erm, you are horizontal, so its easier for your heart. And maybe water resistance stops you working as hard as you want to ? (guess - I know nowt about swimming)

If you look at www.polar.fi - there's a whole mine of info about HR.