Why is space a terrible place for sex? Sexual desire is likely to be curbed by the physiological effects of space flight, such as space adaptation syndrome (onset within 2 hours, and persisting up to a week, experienced by 2/3 trained crew and 85% of those less well trained; includes headache, nasal congestion, dizziness, nausea, vomiting without warning); anxiety about the dangers of space, busy work schedule, lack of privacy. Male  rats experience a decrease in testosterone levels (to less than 20% normal) and this is likely true also for human; anemia, fluid loss, reduced autonomic nervous system function, especially sympathetic tone (needed for climax in both men and women); reduction bone and muscle mass; sex in space may require significantly more energy and higher risk of fractures.

Sex in Space: How Do We Manage To Do It? | Book View Cafe Blog.