If you never raise your voice but spend your evenings arguing with strangers on a screen, that is anger too, and your body is paying the same bill.

What the research says

In a laboratory study of 69 couples, aggression was highest when anger rumination was high, use of reappraisal was low, and alcohol was involved, with these things combining rather than acting alone. Chewing something over is one of the ingredients, not a harmless substitute for acting on it. A separate prospective study of adolescents found difficulty regulating emotion and later symptoms each predicting the other, so the loop can feed itself over time.

Strength of evidence: one line of research. A single study, or a theoretical account.