Just curious as to why you come to that conclusion. It might well be true but it surprises me some.

I'm not surprised that an average European would be in better shape than an average American, but I think an average American bike commuter would be in much better shape your average US citizen.

I've also heard that athletes sweat more in general than non-athletes though that might well be a myth. However if true, being in shape wouldn't necessarily mean you sweat less than somebody else, you may in fact sweat more.