Swimming is one of the greatest types of cardio because you can work your body, but you never have to worry about getting too hot. After doing laps, while my muscles are warmed up, I like to do some strength training moves while I'm still in the pool. If you strap on these Aqua Power Ankle Swim Weights ($38.33), you can feel an amazing burn with the water exercises you already do, like leg lifts, walking in the water, or you can hold onto the edge of the pool and kick. They're great if you like running on the bottom of the pool, or deep water running.
The cool thing about these weights is that they come with five, one pound weights for each ankle, so you can add or remove as many as you want, and change them easily between exercises. They're great if you're bored in the pool and want to try something new. You'll strengthen and tone your muscles and make an already tough workout a little bit more challenging.