I doubt it's age related. There could be medical reasons for it, sure, and perhaps checkin with a doctor, but for some definition of 'normal' you aren't going t

I doubt it's age related. There could be medical reasons for it, sure, and perhaps checkin with a doctor, but for some definition of 'normal' you aren't going to decline at all at 40. Likely more social, emotional, psychological reasons are the cause. Determining what that is, of course, isn't particularly easy, i'm guessing. Good luck to you.