With age, the human immune system becomes less effective at tackling infections and less responsive to vaccinations. At the same time, the aging immune system is associated with chronic inflammation, which increases the risk of almost all conditions linked to old age.
The good news is that exercising and adopting the right diet may help a person maintain healthy immunity into older age.
We live in a time of high average life expectancies. However, our long evolutionary history has adapted us for different lifestyles (and even life expectancies), and these have changed drastically.
As a result, immunity not only weakens in older age; it also becomes imbalanced. This affects the two branches of the immune system — “innate” immunity and “adaptive” immunity — in a double whammy of “immunosenescence.”
“Innate” immunity, which is our first line of defense against infections, fails to resolve after the initial threat has passed, causing chronic, systemic inflammation.
“Adaptive” immunity, which is responsible for remembering and attacking particular pathogens, steadily loses its ability to defend against viruses, bacteria, and fungi.
Meanwhile, the loss of adaptive immunity that comes with older age not only makes people more susceptible to infections; it can also reactivate dormant pathogens that were previously suppressed.
In addition, the weaker adaptive immunity of older adults means that their bodies respond less strongly to vaccinations, such as the annual flu shot.