Irritable bowel syndrome

What it is

IBS is a disorder of gut-brain interaction. The gut is not damaged, but it is hypersensitive: normal amounts of gas and normal contractions are registered as painful, and the motility itself becomes irregular - too fast, too slow, or alternating.

That is not the same as it being in the mind. Visceral hypersensitivity is measurable, and so is the altered motility. What it does mean is that the pathways involved - the autonomic nervous system, stress physiology, sleep and physical activity - are genuine treatment targets rather than lifestyle footnotes.

What it feels like

• Abdominal pain that is relieved, or changed, by opening the bowels
• Bloating that builds through the day and is better in the morning
• Alternating between constipation and looser stools, or predominantly one
• Urgency, and planning journeys around toilets
• Symptoms clearly worse in stressful periods

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

Visceral hypersensitivity

The nerves supplying the gut become more sensitive, so a normal volume of gas or a normal contraction produces pain. This is measurable in the laboratory and it is the core mechanism.

Gut-brain axis dysregulation

The gut and brain signal to each other continuously. In IBS that loop is amplified in both directions, which is why stress produces symptoms and symptoms produce anxiety.

Altered motility

Contractions become irregular, sometimes too fast and sometimes too slow. This produces the alternating pattern many people describe and explains why one treatment rarely fits the whole picture.

Stress and sustained sympathetic tone

Stress alters gut motility, secretion and sensitivity directly through the autonomic nervous system. It is not a psychological explanation - it is a physiological pathway with a well-mapped anatomy.

Inactivity

Physical activity improves IBS symptoms in trials, through motility, stress reduction and probably the microbiome. Being sedentary removes a genuine treatment.

Post-infectious onset

A significant proportion of IBS begins after a bout of gastroenteritis, which leaves lasting changes in gut sensitivity and the microbiome. People can often date it precisely.

Diet triggers, particularly fermentable carbohydrates

FODMAPs are fermented in the colon, producing gas that a hypersensitive gut registers as pain. A structured low-FODMAP trial with dietetic support helps many people; doing it indefinitely and unsupervised does not.

Poor sleep

Sleep disruption worsens gut symptoms and pain sensitivity, and gut symptoms disrupt sleep. It is another of the reinforcing loops.

The microbiome

Composition differs in people with IBS, though cause and effect are not settled. Diet, activity and antibiotic history all influence it.

Anxiety about symptoms

Once eating and leaving the house become risky, the anticipation itself drives symptoms. This is why psychological therapies including gut-directed hypnotherapy have some of the best long-term evidence in IBS.

Who tends to get it

• Anyone who has had a significant bout of gastroenteritis
• People under sustained stress
• Women, in whom IBS is roughly twice as common
• Anyone with anxiety or depression, which co-occurs frequently in both directions
• People with a sedentary lifestyle and poor sleep

What makes it worse, and what settles it

The qFIT routine for this

Ready-made routineDigestion & Gut Comfort

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

Blood in stool, unexplained weight loss, new symptoms after 50, or nocturnal symptoms are NOT IBS - refer

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Exercise produces measurable improvement within about twelve weeks and is one of the few interventions with benefit that persists at long-term follow-up. IBS tends to fluctuate over years rather than resolve, and the useful goal is fewer and milder episodes with less life built around them. Blood in the stool, unexplained weight loss, anaemia, a new onset over fifty or a family history of bowel cancer or inflammatory bowel disease are not IBS features and need investigation first.

Prevalence basis: Gastroenterology population studies

Others the same routine covers

These share the Digestion & Gut Comfort routine, so the work is the same. If one of them also sounds like you, that is a reason to expect more from it, not less.

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.