Swimming and running are your two top ways on that list you provided to lose weight.

I personally prefer swimming over the two because running can cause considerable stress on your knees. Walking alone presses 2-3 times your body weight in force on your knee joint, slowly wearing out your meniscus and bones, running and jumping puts 5 and up times your body weight in force.

I myself have knee issues since I was about 16. So swimming is the way to go for me, when I decide to finally do cardiovascular activities instead of weight lifting that is.

Body building, if done appropriately, will make you gain weight.

Walking..... unless the individual has never exercised and is considerably overweight, the only effect it will have for you is some nice looking calves.

Walking is a good way to lose weight. I walk 2 miles every morning to stay in shape. Throw in a little power walk and it's great for cardiovascular and toning and weight control.

Swimming burns calories pretty fast, an hour of just relaxed laps burns more than 350 calories. If you have a hard time floating, then swimming would be especially beneficial since you'd have to work harder to stay floating.

Miko, I completely agree. My knees are horrible and running is painful.
I like walking, but I always get side aches

I know I intentionally underestimate walking. That is because I assume most people do walk on a typical day. Also it's no where near comparable to the calories burned from swimming and running.

Unless of course as I stated, you have never worked out before, and/or overweight.

To maddie: Side aches? You mean your obliques? You are a swimmer, how are you getting cramps there from walking? The only thing that hurts when I walk too long is my feet and knees -_-. And yes, I really do need to start swimming, my cardiovascular capability is nil. That's it, I'm going tomorrow (I've been procrastinating since beginning of summer from doing so), unfortunately the college pool opens and closes 7-8am.

To OP: All in all the best exercise for you is what you can do that is challenging and you still enjoy it. If for now the best you can do is power walking, then power walking it is, if you can do swimming, then swimming it is, and so on and so forth.

I'm pretty sure its because I breathe incorrectly when I run-- AND I'm talking speed walking here!

I've thought about it, and when I work out in the pool I can easily control when I breathe, how much and for how long-- It's something I really pay attention to actually, which is probably where I get messed up. It's like when you think about your breathing for awhile and then you get a side ache because you aren't breathing correctly?

It sounds so weird when I type it, but I've had this conversation before with people so I know I'm not the only one!

I'm talking power walking.. not just a stroll..
There is a site you can type in your weight and how long you do the activity and it will tell you what you burn. I'm not going to give it because it is from another forum, but here is what it showed for a 130 pound person at 30 mintues:
walking.. 4 mph in 15 minutes= 140 calories
general swimming 30 mintues= 187 calories
general tennis 30 minutes =218 calories
general hose cleaning 30 mintues=109 calories

Aerobics: high inpact 30 mintues=218 calories
sex moderate effort.. 30 mintues= 47 calories

Ahh, that makes more sense. I couldn't take regular walking too seriously.
I'd like to know how they calculated "sex moderate effort". I'm envisioning a white lab with perverted scientists attaching sensors to a couple and asking them to have a go at it with moderate effort and that they will be watching from the other room.

I guess I'm not sure..

My calculator gave me different answers by far. Here's what I got for 130 pound person and all activites for 15 minutes.

Walking 4 mph: 76
Tennis - singles: 90
Swimming - moderate: 90
Swimming - vigorous: 144

But what beats everything from what I remember is working out on an eliptical. I'm pretty sure that beats everything but it wasn't on the poll.

I'd vote swimming and walking:) But what i'm really doing for sometime now are yoga and swimming. Their combination works for me. I've kept my ideal weight since I started doing them regularly;)

see some of my replies on this subject, exercise is overated & should not be done to extremes, walking is good enough. its about giving your body what it needs, not flogging it like a derby looser!