Would you classify sex as "good exercise."?

[Mark]

Depending on how long it lasts and who is on top, it can be decent exercise, yes.

 

[amy]

I read that one of the benefits of a healthy sex life is that sex is "good exercise."

I know next to nothing about sex and I'm a virgin (although getting married in 2 months ). So, for those of you more experienced that I am about sex, is it really good exercise? If so, how is that?

Thanks