Lap swimming

Currently I walk 45 minutes/day four days per week, and I lift weights every other day. I would like to do some lap swimming (for cardio) but every time I have tried, I feel like my heart is going to pound right out of my chest. I thought I was in pretty decent shape, but evidently i am not. I have zero stamina for lap swimming. Does anyone have any advise? jean

Jean, I too started out feeling this way.  I invested in a swimmers snorkel.   It made all the difference in the world for me.   I went from a quarter mile in an hour to a full mile of laps in just under an hour.   It is not that you are so out of shape for the laps, it is the breathing that can mess up the swimming.

I have to agree that the breathing restrictions that swimming puts on you are what sets it apart from other types of aerobic activity.  I swam a lot from a pretty young age, and looking back, it was important for me to learn to breathe every three strokes (that is, to the opposite side that I first learned to breathe).  It balances out your stroke. But more to your point, if you need to start out breathing every other stroke or even using a snorkel as has been mentioned, do it.  I'd get off the snorkel as soon as your body adjusts to swimming, though.