Is there a link between constipation and blood pressure changes?

People with irregular bowel movements often complain about elevated blood pressure that doesn’t respond to medical treatment. In such cases blood pressure usually normalizes naturally after bowel evacuation. So, is there an association between these two ailments?

Spikes in blood pressure and difficulties with bowel evacuation are common complaints of many people. However, few people know that there is a direct correlation between these pathological abnormalities. Even it is often not critical, constipation and high blood pressure affect each other’s development.

Thus, chronic constipation elevates blood pressure, and hypertension becomes the cause of constipation. This happens due to many reasons, among which the main are:

  • Age-related changes due to decrease in blood supply to the gut and its vessel walls weakening, as well as due to their hardening.1 Any impairment in blood flow has a toll on bowl activity. That’s why elevated blood pressure provokes constipation, which is often seen in elderly patients. Moreover, hypertension treatment can also provoke constipation as a side effect, adding to the problem.
  • Dysfunction of smooth muscle fiber in the vessel and gastrointestinal walls (gastrointestinal dysfunction directly affects normal vascular functioning )2. This is explained by the fact that the smooth muscles of vessel and gut walls have the same fibers. Although their number differs considerably, they work on the same principle. That is why lower gastrointestinal tract disorders are often accompanied by blood pressure fluctuations.

Hypotension accompanies constipation as often as hypertension. As a rule, low blood pressure and constipation is a symptom of endocrine disorders.3 The interrelation of low blood pressure and constipation is simple - decrease in thyroid function worsens the tone of both vessel and gut smooth muscle fibers. This deteriorates their normal functioning and, as a result, there appear problems with defecation, and hypotension develops.

In spite of the fact that blood pressure and bowel activity relate to each other, constipation cannot cause a severe rise in blood pressure. Therefore the person is safe from hypertensive crisis. With chronic constipation blood pressure usually rises by 15-25 mm Hg, but such disorder is persistent and can be improved only after evacuation of the bowels.

However, blood pressure can increase when a constipated person is straining to defecate. Excessive straining allows large blood volume to the brain, which can increase pressure in arteries and vessels.

For some people, defecation means straining and holding their breath. This can result in an irregular heartbeat and activate a nerve in the chest that signals the brain to change the heart rate and dramatically lower blood pressure. This puts the body in a panic mode, creating an irregular heartbeat and a rapid rise in blood pressure.

A combination of holding your breath, straining and experiencing abdominal cramps can also stimulate the vagus nerve, which connects the brain and the colon. This can cause a sudden drop in blood pressure and slowing down of the heart rate, which could result in fainting as blood leaves the brain and rushes to the legs.

Considering that there are many factors that predispose a person to constipation, including diabetes, endocrine disorders, hormone imbalance, depression and atherosclerosis, all of which are also risk factors for cardiovascular disease, constipation is proven to be a marker for cardiovascular risk factors and is related to an increased risk of cardiovascular events.4

Since constipation can be easily assessed, it should never be taken lightly as it can be a helpful tool to identify people with increased cardiovascular risk.

References:

1. “Clogged arteries in the gut?” Harvard Heart Letter. Published: July,2016. https://www.health.harvard.edu/heart-health/clogged-arteries-in-the-gut

2. Martins JCS, Mendes LSC, Duraes AR. “Cardiovascular Complications of Gastrointestinal Diseases”. Journal of Gastrointestinal & Digestive System. 5:351. Published: October 24, 2015. https://doi.org/10.4172/2161-069X.1000351

3. Jeesuk Yu. “Endocrine disorders and the neurologic manifestations”. Annals of Pediatric Endocrinology & Metabolism. 19(4): 184–190. Published: December, 2014. https://doi.org/10.6065/apem.2014.19.4.184

4. Salmoirago-Blotcher E, Crawford S, et.al. “Constipation and risk of cardiovascular disease among postmenopausal women.” The American Journal of Medicine. 124(8):714-23. Published: August, 2011. https://doi.org/10.1016/j.amjmed.2011.03.026