Does sex tonight impact your workout tomorrow?

A commonly held belief among many athletes and coaches (particularly male ones) is that sexual intercourse the evening before a competition spells disaster on the big day. Thus, many high-level athletes practice abstinence prior to competition. Muhammad Ali was an outspoken proponent of this rule, as was Marv Levy, head coach of the Buffalo Bills, who separated his athletes from their partners leading up to the SuperBowl.

In conversations with my male friends, the anecdotal consensus certainly was that any bedroom activity decreased the intensity of next day’s workout. Though, of course, this is MUCH less relevant than it would be to competitive athletes. Naturally, I decided to look into this issue more seriously and see if there is any scientific evidence to back up the idea that knockin’ boots the night before might negatively influence athletic performance.

Despite what I consider to be a very interesting and valid scientific query, PubMed and Google Scholar revealed little research on the matter (hint: if you are a graduate student in health science or kinesiology and you’re looking for a neat thesis topic – you’re welcome!).

A decent editorial by McGlone and Schrier published in 2000 discussed the evidence available at that time and came up with 3 studies.

According to these authors,

“All of these studies suggested that sex the night before competition does not alter physiological testing results.”

For example, in one study, 14 married males performed a maximum grip strength test the morning after an evening of horizontal mambo with their wives, and the same test after at least 6 days of abstinence. No differences were found between the 2 conditions. Other studies have similarly suggested no effect of bumpin’ uglies on outcomes such as balance, reaction time, aerobic power (stair-climbing exercise), and VO2max.

The two commonly suggested reasons why intercourse may reduce subsequent performance are physical exertion and a decreased testosterone level among men. First, despite the extravagant stories exchanged between males in locker rooms, a normal session of business time between married partners results in the expenditure of only 25-50 calories, and it’s thus unlikely to influence next day energy stores. Keep in mind, however, that the physiological response to sex with a new partner is markedly different and may results in a few extra calories being consumed. In terms of testosterone level, the evidence I could find suggested no influence of intercourse.

While the above studies certainly suggest no physiological change in response to recent coitus, athletic performance also depends on psychological status. It has been suggested that levels of aggression might be reduced after intercourse, and aggression is thought to influence athletic performance. Unfortunately, I am unaware of research either supporting or debunking this hypothesis.

Thus, until evidence to the contrary becomes available, a good wrestle in the sheets with your loved one is unlikely to affect your athletic performance the following day.

Additionally, if you’re in it for caloric expenditure, then you’re obviously doing yourself some good by including supplemental ‘exercise’ in the bedroom.


McGlone, S., & Shrier, I. (2000). Does Sex the Night Before Competition Decrease Performance? Clinical Journal of Sport Medicine, 10 (4), 233-234 DOI: 10.1097/00042752-200010000-00001

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4 Responses to Does sex tonight impact your workout tomorrow?

  1. Pingback: RSS Does sex tonight impact your workout tomorrow? – PLoS Blogs (blog) | RSS

  2. Intimacy has a greater effect on working out than these Western studies are revealing. A hand grip study is not a good judge of how intimacy affects a workout.

    Whenever the body loses semen there is a loss of strength, this has been known in Eastern and Russian studies, which are not published in Western Journals.

    Next, there are many athletes who have witnessed a loss of “strength” after intimacy, common sense alone tells us that intercourse affects every part of the male body “Chi” or energy is lost when bodily fluids are lost.

    A Chinese study from the 1950’s showed that it takes almost 3 days to replace the fluids loss from intercourse.

  3. Pingback: Links 5/4/14 | Mike the Mad Biologist

  4. Kaleberg says:

    I’m with Joe Namath on this one. He said he never had a problem with sex the night before a game. His main issue was the associated wining and dining and late night carousing in pursuit of sex. I’m not mystical. Sex in the morning usually means a great workout later in the day. Maybe evening sex is different.