It turns out that endurance may not be the key to a great sex life.

A survey of sex therapists has concluded that the optimal amount of time for sexual intercourse was 3 to 13 minutes. The findings will be published in next month's issue of the Journal of Sexual Medicine.

The time, however, does not count foreplay, and the therapists did rate sexual intercourse that lasts from 1 to 2 minutes as "too short." One researchers says he hopes the new study will help ease the minds of those who believe that "more of something good is better."

Experts say prior research has shown that both men and women want foreplay and sexual intercourse to last longer.