The researchers also drew a potential connection between one’s mental health and the dual presence of headache and constipation, as increased prevalence rates of depressive disorders have been reported in people with both conditions (via Korean Journal of Pediatrics). Finally, the study team presented the possibility that the increased release of serotonin may play a role in both constipation and headache, as greater amounts of the chemical have been seen in the mucus lining of the gastrointestinal tract of constipated children.
In other cases, experiencing a headache when you’re constipated may be related to a health condition. This can include fibromyalgia, as many people with the disorder are reported to experience migraine (a specific kind of headache) and/or irritable bowel syndrome (IBS), a signature symptom of which is constipation (per Healthline). Headache and constipation can also be symptoms of celiac disease, in which the body self-attacks in response to gluten ingestion.