I think Carlspackler’s advice is the one I would recommend. ADT turns everything to flab rather quickly and trying to reverse this trend later is much harder. So yes, weights are recommended and you don’t have to “pump iron” either. Ten pound dumbbells are sufficient to perform a range of exercises while you watch TV, listen to an audiobook or music.
As for aerobics, nothing beats walking at a brisk pace for 30 mins - more if you can - outside or on a treadmill; cycling is great as well.
Some people LOVE exercising; I know I used to….but now I view it as a chore and do it grudgingly and only because I know I need it to counteract ADT.
I will still continue to exercise, but in a more relaxed way, not as regimented, and now that spring is almost here I will enjoy digging, planting and hauling bags of mulch and stone - instead of lifting weights indoors.
And Hans, if absolutely none of this appeals to you, screw it all and buy a new wardrobe which hides the flaws and flatters whatever physique is left😉