Sex is now in the same category as interval training for heart health. A good session with a provider should include a lot of low intensity calorie burning activity mixed in with intervals of high intensity anerobic activity culminating in that final all out 100% max HR orgasm or orgasms which is hardly ever seen in marriage these days. By the way, was your cardiologist a female so she could show you what she had in mind?
Sex with yourself may do the trick depending on how kinky you are!!