We are continually under gravity pressure. Did you know that the typical head weighs about 10% of your body weight? That is some pressure on the rest of the body to keep things in alignment. The typical posture of the untrained is one of head forward, rounded upper back and protruding stomach, not particularly attractive to be honest. It is NOT age, it is training. See below (our famous model!)  for two great exercises to arrest the pull of gravity. It is true that the ground is pulling us all back in eventually, do what you can to keep tall and slow down the inexorable draw towards the dirt. Fight it I say!