Just in time for Valentine's Day: Studies show.....
"People who are out of shape are often less motivated to have sex. They tend to tire more easily, and have a lower sex drive and less stamina than folks who work out."
http://www.webmd.com/sex-relationships/features/better-shape-for-better-sex
"The time you spend working out can have unexpected payoffs when you're tangling the sheets. And understanding the link can help you have more explosive results - in the bedroom and the weight room."
http://www.womenshealthmag.com/fitness/fit-women-have-much-better-sex
"You'll definitely have more enjoyable sex if you don't have to worry about getting fatigued or pulling something."