Can Constipation Really Cause Lower Back Pain?

If you have low back pain, you’re not alone. According to the Canadian Chiropractic Association, 85 percent of working people can expect to experience low back pain during their lifetime. One reason the problem is so common is that the list of potential causes for low back pain is long.

Your back contains many structures that can cause or contribute to pain, including bones, muscles, joints, nerves, tendons, disks, and ligaments. These can become damaged from trauma, aging, obesity, overexertion, and underlying diseases, among other factors.

Your lower back’s proximity to other organs and body parts, like the colon, makes it a prime target for referred pain, including from constipation.

Here’s a closer look at constipation, the causes of constipation with lower back pain, and treatment options for relief.

(Related: 11 Signs Your Upper Back Pain Is Serious Trouble)

What is constipation?

Constipation is defined as having three or fewer bowel movements in a week. If you are constipated, your stool may also be hard, dry, and painful to pass.

“Constipation may cause lower back pain because stool buildup can cause pressure on the colon or rectum, which can refer pain to the lower back,” says Yili Huang, DO, director of the Pain Management Center at Northwell Health’s Phelps Hospital in Sleepy Hollow, New York. Pressure from constipation-related abdominal bloating, gas, and swelling may manifest as low back pain, too.

If you already have back pain, constipation may worsen it. Pushing too hard to pass a bowel movement can aggravate your back. It’s also possible that the prescription narcotics you take to treat your back pain are causing constipation, according to the U.S. Pain Foundation.

(Related: 6 Helpful Products for Lower Back Pain)

Causes of constipation with back pain

“If constipation is the culprit of your back pain, the pain is likely along the sides of your lower back,” says Elena Maser, MD, an assistant professor at the Icahn School of Medicine at Mount Sinai and a gastroenterologist at the Feinstein IBD Center at Mount Sinai Hospital in New York City.

Another way to tell? “This pain should resolve if you pass one or more banana-sized stools,” Dr. Maser says.

Constipation may be picked up by your primary care doctor when you are evaluated for low back pain. “Your doctor will likely order an X-ray,” Dr. Maser says. “You can see large stool buildup on the films if you look for it.”

Keep reading for the possible reasons you’re constipated—and how to find relief.

(Related: Why Staying at Home Causes Constipation—and How to Get Relief)

Low-fibre diet

Fibre increases the bulk of your stool, making it easier to pass, which is why low-fibre diets have been linked to constipation and low back pain.

Treatment

The Academy of Nutrition and Dietetics suggests 25 grams of fibre per day for women and 38 grams for men. High-fibre foods include fruits, vegetables, whole grains, and beans.

What you don’t eat is also important, explains Dr. Maser. Foods with little to no fibre—think processed foods, chips, and cookies—won’t help you become more regular, which won’t relieve back pain from constipation. These unhealthy foods may also lead to weight gain, which can cause or worsen low back pain.

Dehydration

Not drinking enough water can cause or worsen constipation, and lead to low back pain.

Treatment

It’s important to drink enough water or unsweetened beverages throughout the day to make sure your stool stays soft. Along with ample fibre intake, water makes stool easier to pass, Dr. Maser says. According to the U.S. National Academies of Sciences, Engineering, and Medicine, an adequate daily intake of water is 11.5 cups (2.7 L) for women and 15.5 cups (3.7 L) for men. Just remember that fruit, vegetables, juices, and even coffee all contribute to your daily hydration.

Lack of physical activity

You’ve got to move to have a movement. Regular physical activity keeps all of your muscles—including those involved in passing stool—in good shape.

Treatment

Aim for 30 minutes a day of moderate physical activity, such as brisk walking, at least five days a week, along with some strength training, according to the CDC. Walking can also help with your back pain.

(Related: 10 Ways You Never Knew You Were Using the Toilet Wrong)

Medications

Your medications, including those you take for low back pain, may cause constipation, which can worsen your pain. The list of medications with constipation as a possible side effect includes narcotics, some antacids, antidepressants, tranquilizers, iron or calcium supplements, anticonvulsants for seizure disorders, blood pressure meds, and drugs that treat the symptoms of Parkinson’s disease, according to the American Gastroenterological Association.

Don’t stop taking a medication, even if it’s the cause of your backup. Talk to your doctor instead.

Make sure your doctor knows about all of the medications you take on a daily basis—including supplements. If you are taking a medication for back pain that is causing constipation, your doctor may be able to prescribe a different one or give you advice on how to relieve your constipation, Dr. Maser says.

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is marked by constipation and/or diarrhea, cramps, pain, bloating, and fatigue, and also travels with low back pain, according to the International Foundation for Gastrointestinal Disorders.

Treatment

Discuss your IBS symptoms with your doctor to see what else you could be doing to feel better. There are many treatments you can try, including medication, stress management, and relaxation techniques.

Bowel obstruction

“When lower back pain is associated with sudden changes in bowel or bladder control, it is important to seek medical attention to ensure that it is not related to dangerous neurologic damage,” Dr. Huang says.

Known as cauda equina syndrome, this rare disorder occurs when nerve roots in the lumbar spine are compressed. These nerve roots (the cauda equina, hence the condition’s name) control bladder and bowel function, according to the American Academy of Orthopaedic Surgeons.

Treatment

Your doctor may order imaging studies, like an X-ray, MRI, or CT scan, to diagnose the disorder. You may need surgery to remove material pressing on the nerves and prevent permanent damage.

(Related: 9 Foods That Can Make Constipation Worse)

Colon or rectal cancer

Sometimes a tumor may block your bowels, leading to constipation and back pain. Other symptoms may include cramping, vomiting, bloating, and the inability to pass gas.

A change in your bowel habits can be a sign of colon or rectal cancer, especially if it lasts for more than a few days and occurs with other symptoms, such as rectal bleeding, blood in your stool, and unexplained weight loss.

The best way to stay ahead of colon cancer is to make sure you undergo regular screening with colonoscopy.

Treatment

If the blockage is complete, surgery may be needed to remove the tumor, according to the U.S. Library of Medicine. Depending on your type and stage of cancer, as well as if it’s spread, you may need additional treatment, such as chemotherapy or radiation, according to the National Cancer Institute.

Pelvic floor dysfunction

Constipation may not be related to your diet and lifestyle at all. Sometimes it’s caused by a lack of coordination between all the muscles involved in having a bowel movement—a condition known as pelvic floor dysfunction, Dr. Maser says.

See a gastroenterologist to learn what type of constipation you have, says Dr. Maser. It may be related to your diet or lifestyle, or it could be caused by pelvic floor dysfunction.

It’s an important distinction, as eating more fibre to increase the bulk of the stool and drinking more water to help it pass won’t work for constipation caused by pelvic floor dysfunction. “It could make it worse,” she says.

Treatment

Treatment involves the use of biofeedback to learn to be more aware of bodily movements or sensations, or pelvic floor physical therapy, which retrains these muscles, the American Gastroenterological Association explains.

Other treatment options for constipation with back pain

Treatment of constipation with back pain typically starts with a capful of an over-the-counter laxative, such as Miralax (polyethylene glycol 3350 powder), taken daily for eight weeks.

“It is gentle enough that people will do it and aggressive enough that it will work,” Dr. Maser says. Miralax works by drawing water into the colon to soften the stool and may stimulate the colon to contract.

Once the initial bout of constipation is resolved, other methods, including eating a high-fibre diet, drinking more water, making medication changes, or learning biofeedback, can help prevent it from coming back.

The last word

Constipation often travels with low back pain. Your first step is to figure out if the constipation is the chicken or the egg. Identifying and treating the underlying cause will benefit your constipation and back pain.

If your constipation is caused by dehydration, lack of dietary fibre, or physical inactivity, there are steps you can take to get regular. “Water helps,” Dr. Maser says. “Exercise helps. A high-fibred diet helps. Eating meals at regular times helps, as does taking time to pass stool and not rushing it.”

Most of the time, constipation is nothing serious, but if you are also bleeding from your rectum, you notice blood in your stool, and you’re losing weight without trying to, check with your doctor to see what is going on.

Next: A Guide to Back Pain Symptoms, Treatment, and Prevention