Smoking cigarettes and drinking coffee can both trigger those sudden, intense bursts of anxiety known as panic attacks.

One key reason: nicotine and caffeine are both stimulants that activate the sympathetic nervous system, making the body more responsive to stress or perceived danger.

In addition, cigarette smoke contains carbon dioxide, which induces the shortness of breath that leads to an attack in many panic-disorder patients. And as it happens, researchers at the University of Rio in Brazil recently found that individuals who are caffeine-sensitive usually belong to this “respiratory panic-disorder” group, as well.

The message is clear. Put out that cigarette and watch your caffeine intake…including the “hidden” caffeine in many sodas and over-the-counter medications.