What causes nighttime stomach cramps?

Unlike an ache or pain that's there one minute and gone the next, stomach cramps are characterised by sudden, involuntary tightening of the tummy muscles - or spasms - that are more intense and cyclic. These cramps can be uncomfortable and may be accompanied by other digestive symptoms, such as bloating, nausea, vomiting, or diarrhoea.

What can cause nighttime stomach cramps?

Knowing the causes of nighttime stomach cramps could help you avoid getting them - or at least have a better idea of when to seek medical help.

Too much, too little, too late

Eating a lot of food close to bedtime - or not eating enough throughout the day - might lead to nighttime stomach cramps. Sometimes these two causes can even overlap.

Angel Luk, a registered dietitian and nutritionist from Vancouver, Canada, explains that going all day without eating - then becoming very hungry and eating a large meal before bed - can increase your likelihood of nighttime stomach cramps.

She adds: "In contrast, if you restrict your eating, and don't provide your body with enough nourishment throughout the day, you may experience hunger pains that can also feel like cramps."

Double board-certified psychiatrist and sleep medicine specialist, Dr Chester Wu, Texas USA, adds that your digestive system slows down during sleep, which can exacerbate conditions such as constipation or gastroesophageal reflux disease (GORD). This is more simply known as acid reflux - a condition where your stomach acid flows back up into your oesophagus, leading to heartburn and tummy discomfort.

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One of the most common causes of nighttime stomach cramps is an undiagnosed food intolerance. When someone has a food intolerance without realising it, this could lead to digestive issues.

Luk says: "Even if you experience discomfort eating or drinking certain foods, you may continue to consume them, unaware that the food and symptoms are connected.

"A typical example might be a habit of drinking a cup of milk at bedtime since childhood - not realising your body's production of the lactase enzyme has decreased, leading to lactose intolerance."

Stress and sleep disruption

Long-term stress and lack of sleep can negatively impact digestion, causing discomfort and cramps. When your body is tense from stress your tummy muscles can become strained, which exacerbates your cramps. Additionally, stress can trigger the release of cortisol - your body's stress hormone. This can increase stomach acid production, and often result in heartburn and tummy discomfort.

"Stress and poor sleep can also create a vicious cycle, where poor digestion worsens sleep quality," says Wu. "This, in turn, increases the likelihood of stomach issues."

Period pains

Menstrual cramps - a common source of discomfort for some people - can cause pain before or during your period. This pain occurs as your womb contracts, causing moderate to sometimes severe cramps that can radiate from your tummy to your back and thighs.

Underlying health conditions

Long-term stomach cramp symptoms may be caused by a range of underlying health issues, such as Reizdarmsyndrom (IBS).

"People living with IBS often deal with stomach cramps at unpredictable times of the day," says Luk. "The triggers are not exclusive to food, as stress can also lead to unwanted cramps at often the most inconvenient times - such as when you’re trying to get a good night’s rest."

Wu adds: "Stress or low-quality sleep can also worsen IBS."

If your stomach cramps - and their associated symptoms - don't get better, you should have them checked out by a doctor to see if you have any hidden health conditions.

Luk advises if your cramps are persistent or severe, you should seek medical attention as soon as possible.

She explains: "This is because the potential causes of your discomfort could be anything from non-life-threatening issues such as lactose intolerance to something much more serious like coeliac disease."

These symptoms don't necessarily indicate a serious health issue. However, they may need to be managed with appropriate treatment or personalised medical advice to address the underlying causes.