Also early 40s and physically very fit here. I have a tendency to get hit hard by respiratory things; i.e. if there's a cough going round I always get it.
I had covid months ago. One day in bed feeling weak and feverish, then up and about feeling more energetic next day. Headaches for a week although paracetamol helped with them. The cough hung around for about three weeks and it wasn't a delight but nothing I couldn't handle and it improved consistently if slowly after the first 10 days. Overall I would say it was at the same level of having a bad, but really odd, cold.
It didn't affect me energy-wise or fitness-wise longer term (besides the slight loss of physical condition from not working out for a week or so). I had no sense of taste for a few days, and no sense of smell for a few weeks, but other than that no lasting effects.
I know several other people who've had it. Family friend (early 50s, very overweight, high blood pressure) who had mostly gastric symptoms, as did his teenage daughter. They had upset stomachs and felt washed out but were otherwise fine after about a week.
A friend's nan had it in June: she's early 90s (!), several health conditions as you'd expect. She 'felt poorly' for a few days and was coughing for a while but has recovered fine. (I tell you, old Cumbrian ladies... they make 'em of stern stuff.)
An ex client... late 40s, asthmatic. Had it in April. In bed for three days, then up and about and recovering steadily apart from slight hearing loss which lasted about two months. (Officially that counts as long covid, apparently.)
One of my DB, SIL and family all tested positive recently but none had any symptoms whatsoever over the course of their isolation.