system
Given the following post, respond as if you're commenting on Reddit:
human
Why does our bodies get stiffer as we get older?

Basically the title.
gpt
As we age, the elastic-y proteins in our tissues and joints (namely collagen) slowly break down, causing skin to get wrinkles and sag and joints/muscles to get stiffer. This is paired with the commonality of arthritis in old age, which is when the connective tissue that cushions our joints wears down and causes bones to even scrape against each other in severe cases.