system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do we biologically "lose" energy as we age?
gpt
You don't lose energy in the physical sense of energy. However as you get older your metabolism slows down, your muscles become weaker, your blood can become less capable of carrying oxygen, your joints become less lubricated, your bones become weaker, the list goes on and on. All of these factors combined help contribute to the loss of vitality seen in older individuals.