I must say, I have noticed a slight difference. I'm 37 and even 10 years ago I could wake up at 4am, go do sprints, then come home, get ready for work. Go for a walk after work and still have energy.
My recovery time was shorter back then, but nowadays it seems like if I go to the gym and have a hard workout which involves weight training and some other cardio post workout, my recovery time is slower.
I am generally still aching for at least a couple days afterwards. Maybe it's just in my mind, but I don't think it is. How is your experience with working out and recovery since being in your 30s, and how do you combat it?