Former President George H.W. Bush's hospitalization a day after wife Barbara's funeral has raised questions about whether stress or a broken heart played a role.

Doctors said Tuesday that medical problems in a surviving spouse may not be due to stress, but it's a good time to give extra support and care.

The 93-year-old former president has an infection that spread to his bloodstream, and he is being treated at a Houston hospital.

Stress can weaken the immune system, making it harder to fight off infections. Sudden shock also can trigger a heart attack or a similar condition called broken heart syndrome.

Barbara Bush died last week at age 92.