This is a question for me and my clients! How do you replace a 45-minute run (oops, sorry, all of you shouting “specificity!” right now. What do you substitute for a 45-min run?)
Climb stairs, check. Many mamas cannot do higher impact movements due to pelvic floor issues.
Do good cardio workout videos exist?
The above are all excellent recommendations. I have an additional one so that hopefully the happy mother can return to high impact activities and is not reduced to any degree of incontinence from here out. Here is a good web site:
Alternatively, check around and see whether you can find a physical therapist who specializes on this therapy.