How much of a workout is sex, really?

(Credit: HBO)
Sex isn’t only a pleasurable experience, with some reports claiming the act also has health benefits that can be compared to those of exercise.
In fact, the physiological response to sex is similar to that of exercise. Landmark studies in the 1960s showed people having sex had an increase in their respiratory rate, heart rate and blood pressure.
These are all signs the body is working at an elevated rate, similar to that experienced during exercise.
More recently, these find