Fatigue is one of the most common IBS complaints outside the gut, yet it's still poorly understood.[1] It's closely tied to what IBS does to the rest of your life: broken sleep, the strain of unpredictable symptoms, and the anxiety and low mood that often come with them.[2]
How common is fatigue with IBS?
Very. A meta-analysis pooling 15 studies found fatigue in about 54% of people with IBS. It was more frequent in women, in younger people, and in patients seen in specialist centers.[1] In a study comparing 100 people with IBS with matched controls, a constant feeling of tiredness was one of the non-gut symptoms that stood out most.[3] UK NICE guidelines list lethargy among the features that are common in IBS and can support the diagnosis.[4]
It isn't trivial. In a Swedish study of 160 patients, fatigue mainly got in the way of physical activity, work, housework and social life, and poor stamina was its most prominent feature.[2]
Why does IBS make you tired?
Researchers haven't pinned down a single cause, but several factors are clearly linked:[1]
- Poor sleep. A meta-analysis of 36 studies found sleep problems in about 38% of people with IBS, more than twice the odds seen in people without IBS.[5] In women with IBS, a poor night's sleep predicted more fatigue, abdominal pain and anxiety the next day.[6]
- Anxiety and low mood. Anxiety symptoms affect about 39% of people with IBS and depression symptoms about 29%, roughly three times the odds in healthy people.[7] Both can drain energy.
- Symptom burden. Severe fatigue went hand in hand with more severe IBS symptoms, anxiety and depression.[2]
- Overlapping conditions. Chronic fatigue syndrome and fibromyalgia are among the conditions most often found alongside IBS.[8]
Can IBS make you feel unwell all over, or pee more?
Yes, IBS often reaches beyond the gut. In the same controlled study, people with IBS reported backache, an unpleasant taste in the mouth and bladder symptoms much more often than controls. The bladder symptoms included waking at night to pee, needing to go often and urgently, and a feeling of not emptying fully.[3] NICE also lists nausea, backache and bladder symptoms as common in IBS.[4]
Don't put new urinary symptoms down to IBS without a check, though. Pain, fever or blood need attention. In women over 40, needing to urinate more often was one of the symptoms linked with ovarian cancer, along with abdominal bloating and distension.[9]
What helps IBS fatigue?
- Get the gut symptoms under control. Because severe fatigue tracks severe IBS symptoms,[2] treating the IBS is a sensible first step. See how IBS is treated.
- Protect your sleep. Poor sleep predicts more fatigue and pain the next day, so insomnia or other sleep problems are worth raising with your doctor.[6]
- Move more, gradually. In a randomized trial, people with IBS who increased their physical activity improved their symptom scores significantly more than controls.[10] About five years later, a follow-up of trial participants found that fatigue, anxiety and depression were better than before the trial.[11]
- Treat anxiety or low mood. They are common in IBS and linked to more severe fatigue,[2][7] so mention them to your doctor.
It helps to track energy alongside gut symptoms and sleep to see what moves together. IBS Clue, an iPhone app coming soon, includes fatigue in its quick check-ins along with bloating, pain and bowel symptoms, each with a severity rating. That makes it easier to spot whether tired days follow bad nights or flare-ups.
When is tiredness a sign of something else?
IBS doesn't cause anemia or weight loss. Guidelines treat both as alarm features that need investigating.[12] Several conditions cause tiredness alongside gut symptoms that can look like IBS:
- Iron-deficiency anemia can cause tiredness, shortness of breath, dizziness and pale skin. It can result from blood loss in the gut or from conditions such as celiac disease that reduce iron absorption.[13]
- Celiac disease can cause fatigue along with bloating, gas, diarrhea or constipation, and belly pain.[14] See IBS vs celiac disease.
- An underactive thyroid commonly causes fatigue, lethargy, feeling cold, weight gain and constipation.[15]
NICE recommends a blood count, inflammation markers and celiac antibody tests for anyone who meets the IBS criteria.[4] See a doctor if your fatigue is severe or getting worse, or if it comes with weight loss you can't explain, blood in your stool, fever, symptoms that wake you at night, or a known low blood count.[12] See also IBS red flags.