The minister who counseled my husband and me before marriage was very up front about Sex and told us that we needed to have a good sexual relationship for the marriage to be whole. He said he and his wife refered to it as their "15 mile hike!" I think somewhere, in all the "calories burned" exercise charts, there must be a chart on how many calories are burned.
It doesn't last long enough to count as a workout, lol... Working out needs to be able to not only raise your heart rate for more than a few seconds but it also must target core muscle or fat groups.
Average sex lasts less than 30 mins. I don't start burning calories till I have been on the tredmill for 15mins and that is at a run. So, No, sex should not be considered a work out since, more often than not, it will not last long.
my husbands doc asked him if he exercises he said occassionaly. then he asked if he has sex regularly. my hubby said yes 2-4 times a week. doc said make it closer to 4 times a week especially if you can't get exercise in at the gym or outside!
as long as you, the female, is active during sex too, you can count it too. work up a sweat!! Dont forget... its fun!! ;-)