DAmn.... A lot of misguided thinking here.
Some answers were right but they just get overlooked, never to be noticed again. wtf?
First I will say I'm no expert, but there are some basic principles to live by. Cardio is just cardio... making your heart work at a certain level. DOESN'T MATTER what the hell you do, as long as your heart rate is xx or xxx or whatever your goal is at that moment. Walk, run, swim, row... it DOESN'T MATTER.
NOW, what DOES matter is the MUSCLES being worked in addition to the walking or swimming. YES swimming works more muscle than wlaking or possibly more intense, but that is not the point of cardio. LIFTING WEIGHTS should be what works your muscles, not swimming or rowing etc... Do you want a huge back from a rowing machine? Do some deadlifts for that. Rowing should be for cardio, swimming should be for cardio, running etc... Don't combine the two things together. Do cardio for cardio's sake and lift weights for muscle building's sake.
IF you don't workout or have time etc... then by all means, swim for a good effect, but if you want an all around training program, then lift weigths AND do cardio. Actually, depending on metabolism etc.. you may not even need cardio for fat loss. blah blah...
Fuck!
I'll be in chat if anyone wants to fight.
Again, honestly, I don't know my shit, but these are BASIC principles everyone should know.
Go read the replies again and see who gave the right answers.
Fuck, I'm getting banned now!