what is a good low impact, high cardio exercise besides swimming and running?

I think that i'm going to have to stop on the running for a while because my ankle has been bothering me off and on for ever since I started running again in February....some days I can hardly put weight on it and some days (most days) it's just fine....but last week I ran and it was aching and then I ran the next day and it's never felt fine since then...even my staff asked me the next day why I was limping...i'm thinking elliptical for awhile? is that a high cardio workout though? i'm used to getting my heartrate into the 180s....also I DO NOT SWIM and am not about to learn

Elliptical could likely hurt your ankle just as much as running. What about one-legged jump-rope, kettlebell swings, stationary bike, rowing machine, battle ropes or prowler, etc.

I also find that my heart can go crazy during strength training as well, so you could always just take 6 weeks to focus on weights instead of 'cardio'...

There are some videos on YouTube called Tonique. Skip the first 6 minutes of the first video because it's all jumping etc. after that she begins a series of squats/lunges etc that leaves me breathless after a minute. My goal is to be able to get through all the videos without collapsing in a heap on the floor. It's all low impact super high cardio.

I like fitness blender on youtube the workouts look easy..but you will put in work. Also you might look into swimming. pilates, and cathe friedrich has low impact high intensity workouts

There's also cycling/stationery bike and rowing/rowing machine as a couple more ideas of low impact exercise. I don't know if they're high cardio though.

Sure, fair enough. I find, personally, that I experience quite a bit more torque in my ankle movement on an eliptical, which in some cases can possibly cause additional damage/pain. But at the end of the day, the easiest way to test what works is to try everything, and see how it feels!

I assume you have access to a gym? I would honestly just use this as a time to play around with different machines to see what works well with your ankle and what meets your cardio needs.

I really like a machine called the Arc Trainer more than the elliptical. Very similar, but I can actually get my heart rate up a lot more. Stationary bike never gets my heart rate up much but it's worth a try, as I imagine everyone reacts differently.