Stress response may differ as well. People with type A blood may produce higher levels of cortisol, the body’s main stress hormone, which could make stress harder to manage.

Blood type can also affect vulnerability to infections. Type O blood may offer some protection against malaria, as the parasite has more difficulty attaching to those cells.

However, type O is not without risks. It has been associated with a higher chance of peptic ulcers, showing that no blood type is entirely protective.

Clotting disorders are another concern. Types A, B, and AB may have a higher risk of venous thromboembolism and stroke due to increased clotting factors.

Other possible links include lifespan, fertility, and type 2 diabetes, though evidence remains limited. Overall, blood type may influence health patterns, but lifestyle, genetics, and medical care play a far greater role.