When people get sexually aroused, do their body temperatures rise, or do they just perceive that they are feeling hotter than usual, as if they are feeling anxious about something?
I remember reading a passage from a Regency romance novel. In one scene, I thought my heartbeat was getting faster. I didn’t know why. I had to reread to know what’s going on, and before I knew it, I could feel my fast heartbeat and I perceived a rise in body temperature. Time passed, and I forgot about the whole issue until I came across a Wikipedia article on Human Sexual Response Cycle. In recollection, I became aware that what I was feeling earlier might be sexual arousal. But the perception of heat… was it flushing or something else? I mean, the feeling was very similar to an even earlier time when I was in middle school and doing public speaking. I interpreted the hotness as nervousness in public speaking, though. Additionally, flushing can occur in sexual and non-sexual situations, such as embarrassment.
I think their surface temperatures can rise because circulation to the surface increases. Core temperatures, not so much, except that once a person becomes physically active in sex (or anything else vigorous) the core temperature can rise.
There are some scientific studies on these kinds of things that could put numbers to it.
The short version is that, yes, arousal can make you both feel warmer (flushing of capillaries near the skin) and actually be warmer (as heart rate, breathing, etc. gear up). Many people experience a “sex flush” where the cheeks, neck and even shoulders and upper chest become red and flushed from this response.
It is similar in many ways to flight or fight responses that you would experience with fear or embarrassment - in all those cases, the body is preparing itself to deal with some kind of potential physical activity.