As others have said, it is mostly downhill from now on, especially with regards to the hair….I mean you just start finding hair in places you cant even believe it could ever grow. And there comes an age where you dont even feel human in the morning unless you have had a daily painkiller.
But good news is that the muscle loss thing isnt necessarily true (unless you take statins in which case ‘bad luck buddy’). My muscles have actually improved since my 40s. One warning though: dont do any exercises that strain joints ‘cos that certainly WILL guarantee the early onset of old age.
Finally….they say the 40s are the best years of your life….its TRUE! Enjoy being more confidant and smart than all those dopey kids with their tuneless music and dubious fashions.