activity can directly cause death, particularly due to coronary circulation complications, which is sometimes called coital death, coital sudden death or coital coronary. However, coital deaths are significantly rare. People, especially those who get little or no physical exercise, have a slightly increased risk of triggering a heart attack or sudden cardiac death when they engage in sexual intercourse or any vigorous physical exercise that is engaged in on a sporadic basis. Regular exercise reduces, but does not eliminate, the increased risk. Duration and genital complications Sexual intercourse, when involving a male participant, often ends when the male has ejaculated, and thus the partner might not have time to reach orgasm. In addition, premature ejaculation (PE) is common, and women often require a substantially longer duration of stimulation with a sexual partner than men do before reaching an orgasm. Scholars, such as Weiten et al., state that "many couples are locked into the idea that orgasms should be achieved only through intercourse [penile-vaginal sex]," that "the word foreplay suggests that any other form of sexual stimulation is merely preparation for the 'main event'" and that "because women reach orgasm through intercourse less consistently than men," they are likelier than men to fake an orgasm to satisfy their sexual partners. In 1991, scholars from the Kinsey Institute stated, "The truth is that the time between penetration and ejaculation varies not only from man to man, but from one time to the next for the same man." They added that the appropriate length for sexual intercourse is the length of time it takes for both partners to be mutually satisfied, emphasizing that Kinsey "found that 75 percent of men ejaculated within two minutes of penetration. But he didn't ask if the men or their partners considered two minutes mutually satisfying" and "more recent research reports slightly longer times for intercourse". A 2008 survey of Canadian and American sex therapists stated that the average time for heterosexual intercourse (coitus) was 7 minutes and that 1 to 2 minutes was too short, 3 to 7 minutes was adequate and 7 to 13 minutes desirable, while 10 to 30 minutes was too long. Anorgasmia is regular difficulty reaching orgasm after ample sexual stimulation, causing personal distress. This is significantly more common in women than in men, which has been attributed to the lack of sex education with regard to women's bodies, especially in sex-negative cultures,