Children have the same stress alarm that adults do, and when it goes off the body releases stress hormones and fast nerve signals to prepare for danger, even when the danger is only a spelling test.

Younger children rarely describe themselves as stressed. Instead they say their tummy hurts, their head hurts or they can’t sleep, which is why the body is usually the first place a parent notices it.

The digestive system is a big part of this. It contains millions of nerves connected directly to the brain, so worry can be felt as real cramps, a queasy feeling or a sudden need for the bathroom.

Teenagers often show it a little differently. Alongside the headaches and tummy aches, they are more likely to become irritable, withdraw from the family, sleep badly or lose concentration.

The pain is real. Children who get stress tummy aches often have more sensitive gut nerves, so ordinary digestive activity that another child would never notice can register as genuine pain.

Stress also interferes with sleep. A worried brain takes longer to switch off at night, and a short night makes the next day’s worries feel bigger and every ache more noticeable.

That is how the loop forms. The pain makes school harder, dreading the pain adds another layer of worry, and eventually the alarm starts responding to smaller and smaller triggers.

The encouraging news is that children’s stress responses are remarkably open to change. Calm adults, predictable routines and consistent sleep all gradually turn the alarm back down.

Recurring tummy pain with no disease behind it is the most studied physical stress sign in children. A 2025 review pooled 66 studies covering more than 200,000 children aged 4 to 18, and found it in about 1 in 9 worldwide.

The estimate for North America was lower, at close to 1 in 13, with a wide margin of uncertainty. Girls were affected more often than boys, and the review named stress, worry, difficult life events and poor sleep as common contributing factors.

A large Swedish study of 2,588 children aged 10 to 18 found the same connection at school. Children who were harassed by classmates, pushed hard with schoolwork or treated badly by teachers reported far more weekly headaches and tummy pain.

In that study, sadness, nervousness and irritability explained most of the connection. In other words, the feelings came first and the body carried them, which is exactly why the body is so often where a parent notices stress before anything else.

Researchers can watch a stress response happen in real time. In one study, 82 healthy children and teenagers gave a short speech and did mental arithmetic in front of strangers. Nothing physical happened to them, yet their bodies clearly reacted.

The teenagers in that study, aged 13 to 17, reacted more strongly than the younger children, releasing more stress hormone and showing a bigger rise in blood pressure. Researchers see this as a normal change during adolescence, not a warning sign by itself.

A second study used the same kind of speech task with 81 young people. When a parent sat with 9 and 10 year olds beforehand, their stress hormone did not rise at all, but with 15 and 16 year olds, a parent’s support made no measurable difference.

That does not mean teenagers don’t need you. It means their support network is widening to include friends, and that your help probably works in other ways, like protecting sleep, keeping routines predictable and simply being available to listen.

It is not only big events that matter. In a study that telephoned families every evening, 154 children with recurring tummy pain and 109 other children described their daily hassles and their physical symptoms.

On days with more hassles, children reported more physical symptoms. The connection was strongest in children who already had tummy pain, which suggests that some children are simply more tuned in to stress in the body.

Difficult experiences also build on each other. In a Danish study of almost 3,000 teenagers, those who had lived through two or more difficult life events by age 15 reported physical symptoms more often, and tension at home showed a similar pattern.

Being bullied is one of the clearest triggers of all. Pooling 30 studies, bullied children were about twice as likely to have headaches, tummy aches or sleep trouble, and the studies that followed children over time found the same result.

Stress is common, but it is rarely the only explanation. Many other everyday things cause the same headaches, tummy aches and moods, and they are worth checking before you settle on stress as the reason.

Sleep is the biggest one. A CDC analysis found that close to 6 in 10 middle schoolers and about 7 in 10 high schoolers were not getting enough sleep on school nights, and tired children get more headaches and shorter tempers.

Screens tend to push bedtimes later. A review of 67 studies found that screen time was linked to shorter or later sleep in 90% of them, although the researchers could not prove that screens were the actual cause.

Then there are the simple ones: a skipped breakfast, not enough water, constipation, caffeine or energy drinks, a cold coming on, a new medicine or the hormone changes of puberty. A quick check with your pediatrician can rule these out.

Children’s stress symptoms often respond well to help. In one trial, 53 children aged 8 to 18 with long-running tummy pain had six sessions of relaxation-based hypnotherapy, and a year later 85% were doing well, compared with 25% on usual care.

Parents matter here too. In another study, mothers completed a stressful task and then held their babies, and the babies’ bodies picked up on their mother’s stress, reacting in step with her.

That is a good reason to look after your own stress, not a reason for guilt. Nearly half of US parents say that on most days their stress feels completely overwhelming, and a calmer adult gives a child a calmer place to settle.

Physical activity helps as well. A review of reviews found that regular activity had a small benefit for worry in young people, while heavy screen time consistently went along with poorer mood.

One belief deserves retiring: that stress tummy aches are made up to get out of school. In a small study, children with this pain had gut nerves that registered pressure as pain sooner than other children did. The pain is real.

Some popular fixes have also fallen short. A trial in 84 UK schools taught mindfulness to 8,376 students aged 11 to 14, and a year later they were doing no better than students who were taught as usual.

Talking therapy shows mixed results too. A major review of 18 trials found that it helped children with tummy pain right after treatment, but the benefit was no longer clear several months later.

Even measuring stress in children is difficult. Many laboratory tasks that reliably stress adults fail to raise the stress hormone in children at all, so hold any single number loosely and trust the pattern you see in your own child.