Why does our immune system weaken as we age?


And why does what causes it to weaken even occur?

In: 2

The organ in which T cells mature, the thymus, atrophies. This reduces your body’s ability to fight infections, especially viral. Generally speaking, your bone marrow where immune cells are made also becomes replaced with fat and becomes less productive. As we age, or cells accumulate oxidative damage that reduces their ability to replenish themselves. There’s a lot of factors that contribute to our immune system weakening as we age, but these are a few of the major ones.

In the big picture of things, because there was no evolutionary pressure for humans to live any longer than after child-rearing, we age. Non-reproductive group members that would live to 120 don’t better pass their genes, and old resource-consuming extra tribe members may actually select against the genes of their offspring.

Faster generations are also preferred by evolution itself – why micro-organisms can out-evolve humans and even antibiotics.