I noticed a thread on "Dating..." (http://forums.aboutmecfs.org/showthread.php?1104) and "Sex and FM and ME/CFS" (http://forums.aboutmecfs.org/showthread.php?579). I would like to start a related thread on sexual activity and post-exertion symptom exacerbation in CFS. There appears to be limited research on sexual function in females with CFS and no research whatsoever in males with CFS as far as I am aware of. Although patients describe how symptoms interfere with their relationships and sex life, not much has been said about symptom exacerbation after sexual activity. It would strike me as odd if this experience was not common for CFS patients even when physical activity is minimal (considering the obvious sensory, emotional, and autonomic demand). Obviously there are both positive and negative effects to consider and weight up. Of course, I am not talking about the normal refractory period and immediate but transient sleepiness that many males experience, or sexual dysfunction in terms of impotence or loss of interest (although a reduced drive is understandable in CFS), or "post-coital headache" (although headache symptoms can be exacerbated), or guilt/shame associated with sexuality. In my experience, too much exertion of any kind (mental/emotional/sensory/physical) leads to a worsening of symptoms in general, and while there is fundamental overlap between the adverse effects of any kind of exertion, there are also some differences that are more specific to the type of exertion (eg too much walking has similar but not identical adverse effects as too much thinking). There exists a forum on something called "Post Orgasmic Illness Syndrome" (POIS): http://www.thenakedscientists.com/forum/index.php?topic=6576.0. After skimming through some of the messages, it appears that these people are also from a "heterogeneous" group, but most appear to be healthy except for the fact they experience a range of cognitive and physical symptoms (but not necessarily the same as those of CFS) only after sexual activity . These people describe the negative impact that "POIS" has on their lives, the struggle for medical recognition from doctors, and what helps their condition. Most insist that their experience cannot be attributed to psychological factors such as depression and sexual guilt. Some note an association with anxiety disorders and medical conditions (eg IBS, hormone deficiencies). A few have CFS but that is the exception. Also see http://en.wikipedia.org/wiki/POIS. I am not directly comparing these two conditions, and I believe that my above mentioned experience has more in common with CFS than POIS because it appears to be secondary to CFS. What do others here experience?