I'm 40 and the only really significant difference from just a few years ago are joint problems when lifting - primarily elbows, shoulders and more rarely knees.
Shoulder impingement for months (more or less over that but still occasionally shoulder pain in either shoulder), elbows popping and snapping and cracking loudly from something as light as standard push-ups - also have more or less severe elbow and wrist pain (including but not limited to a trapped ulnar nerve for a while) that comes and goes.
I used to be able to lift heavy in the gym for two decades with just light warm-ups (which in hindsight might be what has caused some of these later issues) but the last almost two years I've completely dropped my gym membership and switched to calisthenics, heavy duty elastic bands (from Bodylastics) and still dumbbells for some exercises. All of it with a lot of focus on and changes to hand positions and angles to minimize direct heavy load on elbows and shoulders in problematic positions.
I still think it's possible to improve these joint issues though as they are most likely more from muscle imbalances than actual joint problems - some of the small surrounding muscles not keeping up well enough anymore perhaps without further strengthening.
Other than that I'm slightly leaner than I was through most of my 20s and 30s - and on track with my diet to lose the remaining 3-4 kgs to get down to around 10-12% body fat, no obvious drop in muscle mass that I've noticed (I've never been "jacked", just athletic), core strength has never been better, recovery time still seems good, rarely feel tired and cardio health is better than it has been at many times throughout my life.
Shoulder impingement for months (more or less over that but still occasionally shoulder pain in either shoulder), elbows popping and snapping and cracking loudly from something as light as standard push-ups - also have more or less severe elbow and wrist pain (including but not limited to a trapped ulnar nerve for a while) that comes and goes.
I used to be able to lift heavy in the gym for two decades with just light warm-ups (which in hindsight might be what has caused some of these later issues) but the last almost two years I've completely dropped my gym membership and switched to calisthenics, heavy duty elastic bands (from Bodylastics) and still dumbbells for some exercises. All of it with a lot of focus on and changes to hand positions and angles to minimize direct heavy load on elbows and shoulders in problematic positions.
I still think it's possible to improve these joint issues though as they are most likely more from muscle imbalances than actual joint problems - some of the small surrounding muscles not keeping up well enough anymore perhaps without further strengthening.
Other than that I'm slightly leaner than I was through most of my 20s and 30s - and on track with my diet to lose the remaining 3-4 kgs to get down to around 10-12% body fat, no obvious drop in muscle mass that I've noticed (I've never been "jacked", just athletic), core strength has never been better, recovery time still seems good, rarely feel tired and cardio health is better than it has been at many times throughout my life.