Is treading water a good cardiovascular workout?

It’s not bad, but I honestly wouldn’t risk it. What if a small splash leads to an infection?

Vigorous treading can be a great workout. One tough drill is to lift your arms out of the water while treading. Alternate arms in and out. Try this with a freestyle/crawl kick—it can be brutal!

This won’t achieve the results you’re hoping for. Consider alternatives like an exercise bike. Zwift offers excellent structured cardio workouts. By the time you’re ready to swim again, you’ll be in fighting shape.

@Lex
Thank you! I’ll explore that. A rowing machine is also on my mind.

Tanner said:
@Lex
Thank you! I’ll explore that. A rowing machine is also on my mind.

Rowing machines are also a fantastic choice. I’ve used both. If you want long sessions (1 to 2 hours), I’d recommend the bike; it’s easier than maintaining a rower for that long. But this is just my opinion; follow your heart, haha.

Tanner said:
@Lex
Thank you! I’ll explore that. A rowing machine is also on my mind.

Rowing is excellent!

Any exercise that raises your heart rate and makes you out of breath counts as a good cardiovascular exercise. If treading water does that for you, then it is effective.