Both good and bad can happen. I put in a full exhausting day of climbing at altitude and had zero sex drive or energy left for an eager hiker who I met and slept in my tent that night. But then on another occasion, also at altitude, I was soo fully charged up with a strong sex drive, that I was able to bone her twice within 90 minutes, which is well better than my usual turn around time. Both were when I was in late 20, early 30's.
Also a note of interest. IF you are into mountaineering or hiking at higher altitudes for some length of time,,.......or if you read expedition books with pics of guys who were on multi month trips to over 15,000 ft...besides being in good shape, they tend to lose some weight and pics show some very muscular looking veiny arms. Well guess what...it's not just your arms that get 'veiny' ! The lower air pressure at altitude can cause your cock to get somewhat bigger, thicker, as it expands with arousal and your blood fills it up,, and veins stick out more on your throbbing dick, compared to back down at sea level. With my small dick to start, I was so thrilled to see THAT happen to me when the tent fucking time came around on one trip . Girl was surprised as all hell and said she could feel the difference of that veiny, thicker cock when it was stuffed inside of her. I'd love to LIVE up there all the time, just for the nice perks' to my cock. !!
