An acquaintance of mine recently told me how he wants to have a 'swimmers physique' and it got me thinking...all those swimmers in the summer olympics are very well built. whats it about swimming that makes it such great cardio?

You're using just about every muscle your body has to propel yourself through water, as quickly as possible. That sort of fast-as-I-can-go workout requires more muscle than distance training, and it still burns TONS of fat. Think about the difference between a marathon runner and a sprinter- Marathoners are these very skinny, almost malnutritioned looking bunch while sprinters actually have quite a bit of muscle on them- The body adapts to whatever you throw at it, so when you're using all those muscles to push and pull yourself through the resistance of water at a fast speed, your body knows it needs more muscle to handle it, and it burns tons of fat for energy- And because it knows you can't be carrying all that useless weight through the water.

so...would swimming be a good form of cardio instead of running while cutting?

i don't know if i'd completely agree with this mentality.  when i was a hard core swimmer in high school i noticed that i always had a layer of fat on me.  i spent in excess of 5 hours a day in the water doing different activities from teaching lessons, workouts, competitions, water polo and more.  i was given the honors of having the "best physique" by the chicks that were involved with the team, but  i always noticed that i had more fat than i thought i shoud have at my level.  from what i understand...your body maintains a layer of fat to protect itself from the cold.  in this respect, it is quite a bit different than other forms of cardio even though you can possibly burn more calories if you know what you are doing...which most people don't...it's easier to run.  even if you swim in warm water, which you shouldn't, it is still colder than your core temperature.

Maybe you didn't eat enough in comparison to the amount of training you were doing?

hmmm...can't remember...that was such a long time ago, but i do not remember being starved...i did swim in workouts 3500-5000 yds at least twice a day most times more and also did other activities along with this.

Swimming is great exercise, but it's not the best way to get "cut".  Stick with running for that.  When I swam in college I was in great shape, but I still had to run (sprints) in order to be real cut.  Part of this may be that while on the swim team I'd be STARVING after practice, but I still tended to eat healthy.  It could be that you can't lose all of your fat by swimming since it's not a "full body weight" form of cardio like running is.  That said, my shoulders never looked better than back in my swimming days!  It was a great all around workout.  It's like lifting and doing cardio all in one.  It's probably the hardest sport that I ever participated in (and that list includes baseball, football, basketball, and track). 

Running is more effective for cutting.

If I were to choose swimming as my cardio workout, how often should I do it, and how many laps/how much time should I do each time?  I assume swimming fast (but at a regular pattern) is important?
 
Thx!

well...there may differnt opinions on this, but i personally believe that it is important to swim correctly if you are to get anything out of it.  there are main four strokes and several other minor strokes that work the differnet muscles.    the thing is that few people know how to do these strokes correctly and you could end up injuring yourself or being counterproductive.
 
when i swim, i concentrate on the longest stroke possible.  this gives me time to concentrate on technique, which in turn developes the muscles i need for the sport.  i would not recommend just jumping into the pool or lake if you are casual swimmer and really dont know anything about swimming.  i've actually watched people get worse the more they tried because they didn't know what they were doing.
 
one thing that most people don't do is breath correctly.  this is the most important element in swimming and the first thing i always taght to my classes.  you should always, always, always breath just like you do when your not in the water...in and out (ie when in the water, blow bubbles then breath).  if you hold your breath, you are going to dramatically decrease the quantity and quality of your workout and not to forget your confidence level.
 
as for how far and long you should work out...that really depends on your abilities.  i generally swam 3-5,000 yds at a shot using the various strokes, drills, and kicking routines.  you can mix it up everday or workout. 

Thanks for the reply, Devonly.  When you said "breath just like you do when your not in the water", did you mean "not hold breathe under water"?  I always breath out under water instead of holding breath.  I assume that's correct?  I do feel out of breath much quicker when I do freestyle compared to breast stroke, but perhaps that's because of that being a more vigorous style?
 
By the way, I was thinking about using swimming as my HIIT training (I don't like running), which I understand you're supposed to go fast for like 30s or 1 min and then slow down and then do it all over again.  That's why I mentioned "swimming fast".  When you say "long strokes", are you referring to the motion or time?  Since I'm supposed to "sprint" in HIIT, so should I do complete/full/long strokes, but do them quick and more powerful?
 
I've tried swimming laps "leisurely" before for better body shape and it didn't seem to do too much for me, so I thought maybe I was swimming too slow (though it could also be because I only swam 1 to 2 times a week)!

ORIGINAL: Simonight

When you said "breath just like you do when your not in the water", did you mean "not hold breathe under water"?

exactly...just like on land, the slower you breath when you work out the better you'll feel.

ORIGINAL: Simonight

I do feel out of breath much quicker when I do freestyle compared to breast stroke, but perhaps that's because of that being a more vigorous style?

this doesn't have to be like this, i suspect that you do not get into a comfortable rythm.  if you cannot swim 250 yds without stopping, you likely are not getting in a comfortable rythm or your stroke needs work.

ORIGINAL: Simonight

By the way, I was thinking about using swimming as my HIIT training (I don't like running), which I understand you're supposed to go fast for like 30s or 1 min and then slow down and then do it all over again.  That's why I mentioned "swimming fast".?

Swimming is a great cardio workout, but unless you are willing to put in the laps, i don't think that it'll make a very good substitute for hitting the track.

organize yourworkout like this:  warmup (500 yds), drills/kicking (500 yds), core set-100 yds or greater (1000 yds), sprints for your HIIT training-nothing greater than 100 yds (500 yds), warmdown (500 yds).  note when i say "500 yds" this could mean any combination equaling 500 yds or more (ie 5 X 100, 10 X 50, 20 X 25, etc).

also do not forget to use a clock...you can use a watch, but a pool clock is better...(you'd be surprised how disfunctional you get after a good solid workout).  The reason is that you want to be consistent in your start times.  for instance, you may do 10 X 50 yds @ 45 or 60 sec.  this will determine how much rest you'll get.  just a hint...no rest for slackers.

ORIGINAL: Simonight

When you say "long strokes", are you referring to the motion or time?  Since I'm supposed to "sprint" in HIIT, so should I do complete/full/long strokes, but do them quick and more powerful?

i say "long strokes" simply because it forces you to do the stroke correctly.  Correct technique, to me, is right behind breathing in importance.  without correct technique, your stroke is less efficient and wasteful in some/many cases.  of course, your stroke will be shorter if you are sprinting, but for the most part your stroke should be long.  see how few strokes you can do from wall to wall without losing speed...you'll be surprised.

ORIGINAL: Simonight

I've tried swimming laps "leisurely" before for better body shape and it didn't seem to do too much for me, so I thought maybe I was swimming too slow (though it could also be because I only swam 1 to 2 times a week)!

like i said...with swimming you have to put in the laps.  you can't jump into the pool for thirty minutes two, three, or four days a week and expect great results.  i recommend 3-4 times a week, 2500-3000 yds minimum or just don't have high expectations.