Stress gives me diarrhoea then constipation. What can I do?

When you are stressed, it is common to swing between diarrhoea and constipation, or to feel uncomfortably bloated. That is because your gut has its own nerves that are in constant contact with your brain, and stress can make food move through too quickly or too slowly. The UK's NHS suggests things you can do yourself: eat at regular times without rushing, drink enough, cut back on caffeine, alcohol and fizzy drinks, stay active and find ways to relax. If symptoms last more than 4 weeks, you have unexplained weight loss, or you see blood in your poo, see a doctor.

Why does stress give me diarrhoea and then constipation?

In short, your brain and gut talk to each other all the time, and stress can make your gut work faster or slower than usual. When food moves quickly, stools are loose; when it moves slowly, they become hard or you do not feel the urge to go. That is why the same person can swing from one to the other.

Your gut has its own nerves

The US NIDDK, part of the National Institutes of Health, explains that hormones and nerves work together to control digestion. The walls of your digestive tract contain their own network of nerves. When food stretches the gut wall, these nerves release substances that speed up or delay the movement of food, and they control the muscle contractions that push food along.

Speed decides how watery your stool is

The NIDDK says the large intestine absorbs water and changes waste from liquid into stool. If waste passes through quickly, less water is absorbed and stools are loose. If it passes slowly, more water is absorbed and stools become hard and difficult to pass.

Stress scrambles the signals

The NIDDK explains that when communication between the brain and the digestive tract is disrupted, food can move through the gut at the wrong pace. The NHS links this kind of unsettled gut to food passing through too quickly or too slowly, and to stress, so during stressful periods your gut may react more strongly than usual. The NHS Every Mind Matters service also lists stomach problems among the physical signs of stress.

Things that can make it worse

The NHS lists things that can make tummy pain, bloating, diarrhoea or constipation worse:

• alcohol
• caffeine
• certain foods, such as spicy or fatty food
• stress and anxiety
• some medicines

During stressful periods these often come together. Deadlines mean skipped meals, more coffee to stay alert and quick, heavily seasoned takeaway food, and your gut feels it.

Are bloating and irregular bowel movements a sign that something is wrong with my gut?

Usually not anything serious. Bloating and irregular bowel movements most often come from everyday habits. But you cannot tell on your own whether that is all it is, so if it keeps going or comes with warning signs, a doctor should look for the cause.

Common reasons for bloating

The NHS says the most common reason for bloating is a lot of gas in your gut, which can come from:

• certain foods, such as cabbage, beans and lentils
• fizzy drinks
• swallowing air while you eat, for example eating quickly or talking while eating
• constipation
• hormonal changes around your period

Everyday causes versus signs to see a doctor

A simple check is to compare with your own normal: has your bowel pattern changed, and for how long? If constipation is the main problem, read more in What causes constipation, and how can I look after myself?

My stomach plays up when I'm stressed. How can I look after it?

The NHS suggests starting with when and how you eat, what you drink, staying active and making time to relax. None of this needs a complete change of lifestyle.

Eat at regular times, without rushing

• Do not skip or delay meals. In busy weeks, prepare simple food in advance.
• Do not eat too quickly. Sit down for meals instead of eating at your desk or on the move.
• Eat a varied diet and avoid lots of fatty, spicy or processed food.

Add vegetables, fruit and grains gradually

Fibre is found in vegetables, fruit, wholegrains, beans and nuts. If you usually eat few vegetables, add them a little at a time so your body can adjust, and notice which foods leave you bloated. In Thai food, ordering extra vegetables with a one-plate dish or swapping white rice for brown rice at some meals is an easy daily change.

Drink enough and limit some drinks

When you have diarrhoea, you lose more fluid. The NHS advises drinking lots of fluids, taking small sips if you feel sick.

Stay active

The NHS recommends getting plenty of exercise, and NHS Every Mind Matters says being active regularly can help burn off nervous energy. A brisk walk after a meal, taking the stairs, or standing up every hour when you sit at work all count.

Find ways to relax that you will actually use

NHS Every Mind Matters suggests several ways to deal with stress:

• pause for a few minutes to breathe, which can help you feel calmer
• break big tasks into smaller, more manageable chunks
• plan ahead for days or events you know will be stressful
• talk to friends, family or colleagues you trust
• take time to think about the good things in your life

Leaving yourself time in the morning to use the toilet without rushing also helps during busy periods.

I feel bloated a lot. What can I do myself?

The NHS suggests the following:

If you are bloated and constipated, the NHS suggests eating high-fibre foods. Some fibre-rich foods, such as beans and cabbage, can also cause gas, so add them gradually and notice what suits you.

When should I see a doctor about alternating diarrhoea and constipation?

The NHS advises seeing a doctor if you have had tummy pain, bloating, diarrhoea or constipation for more than 4 weeks, or if you feel bloated regularly or changing your diet has not helped.

Get an urgent appointment

The NHS advises getting urgent advice if you:

• have a lot of unexplained weight loss
• have bleeding from your bottom or bloody diarrhoea
• find a hard lump or swelling in your tummy
• are short of breath, notice your heartbeat and look paler than usual
• have diarrhoea for more than 7 days, signs of dehydration, or cannot keep fluids down
• are bloated and also vomiting, have a fever, or cannot poo or pee

The NIDDK says black, tarry stools are also a sign to have checked, and that doctors will also take into account any family history of digestive problems.

Go to the emergency department straight away

The NHS advises emergency care if you have sudden, severe tummy pain, vomit blood, or have a lot of blood coming from your bottom.

Before your appointment

• Keep short notes for a while to show your doctor: meals, drinks, toilet times, what your stools are like and which days were stressful.
• Say when it started, how often it happens and whether it is linked to stressful periods.
• Tell your doctor if anyone in your family has had digestive problems.
• Do not keep using any medicine to stop diarrhoea or help you go without talking to a doctor or pharmacist first. If you are pregnant or take regular medicines, always ask first.

If stress itself is weighing heavily on your eating, sleep or work, talking to a doctor can help you look after both your gut and your mind at the same time.