Migraine starts in the brain, not in the scalp or the neck. People who get it have a nervous system that reacts more strongly to change, whether that change is light, sleep, hormones or stress.

The pain comes through the nerve that senses the face and the coverings of the brain. During an attack, that system turns up its volume, so a normal heartbeat can feel like a throb.

Stress acts on the same control centres that set sleep, appetite and alertness. Keep them on high alert for long enough and the threshold for an attack slowly drops.

The build-up is often quiet, and many people feel tired, yawn, or lose focus a day before the pain, and read those early signs as normal wear from a busy week.

Timing is the twist, because in a small diary study attacks were more likely in the hours after stress eased than during the stress itself. Doctors call this a let-down migraine.

That is why so many attacks land on a Saturday, the first day of a holiday, or the evening a big project ends. The body shifts gears, and a primed brain tips over.

Then the attack becomes its own stressor, as lost days, cancelled plans and dread of the next one keep the alarm system busy, even on the days when nothing hurts.

Painkillers help, but taken on too many days they can make attacks more frequent. That loop, more than stress alone, is how occasional migraines often become frequent.

Your brain runs a stress system built for short emergencies. It sharpens attention, shifts energy and then, when the danger passes, winds back down. For most people that swing is smooth and goes unnoticed.

In migraine, the swing is less smooth. One leading model describes migraine as a brain that carries more wear from repeated stress, so each new strain lands on a system that is already on edge.

The pain itself runs through the nerve that serves the face, scalp and the coverings of the brain. Once an attack starts, that pathway amplifies ordinary signals, which is why movement, light and sound all make it worse.

None of this means the pain is imagined, exaggerated or chosen. It means the brain is doing a genuinely useful job, noticing change, a little too well and a little too often.

Two systems answer a demand. The fast one runs through the nerves in seconds and raises alertness, while the slower one runs through hormones over minutes and keeps the body in that state for hours.

You can see the effect with a purely mental task. In one study, 22 people with migraine, tested on a headache-free day, did an hour of demanding mental work. They built up more pain in the neck and temples than healthy people did.

Their pain also faded more slowly once the task ended. Muscle activity looked the same as in the healthy group, so the change was in how pain was handled, not in tighter muscles.

A brain scan study of one person, scanned every day for a month, found a deep control centre grew more active in the day before each attack. It is a single case, but it fits the early tiredness and yawning so many people report.

Stress does not have to be dramatic to count, because in 5,159 adults followed for two years, each ten-point rise on a stress scale came with about four percent more migraine days a month, and the link was strongest in younger adults.

The more surprising finding is about timing. In a three-month diary study of 17 people, the level of stress on a given day did not predict attacks. A drop in stress from one evening to the next did.

The odds of an attack rose by up to about two times in the following 6 to 18 hours. It is a small study from one specialist clinic, so hold the exact number loosely, but it matches what many people with migraine describe on their own.

Weekends add their own push. In an older clinic survey, people who drank a lot of coffee on weekdays and slept in on weekends had far more weekend attacks, likely from a skipped morning cup as much as the extra sleep.

Stress is rarely the only trigger in play. When 1,207 clinic patients rated their triggers, stress came first at about 80%, but hormones, skipped meals, weather, poor sleep and strong smells were each named by 4 to 6 in 10.

Hormones matter a lot, since migraine is about three times as common in women as in men, and 65% of women in that clinic group linked attacks to their cycle. That is not stress, and it deserves its own plan.

Sleep is more specific than people think. In a six-week study of 98 adults, short nights alone did not predict attacks, but broken, restless sleep came before more of them.

Caffeine sits somewhere in the middle, because in the same group one or two drinks a day showed no clear effect, while higher intake looked like a possible trigger. Bright or flickering light, alcohol and long desk days round out the list.

Each attack is itself a stress on the body, since lost sleep, missed work and fear of the next one feed back into the same system, which is one reason attacks can slowly become more frequent over time.

Painkillers are the other big driver. Simple pain relief on 15 or more days a month, or migraine-specific drugs on 10 or more, for over three months, can cause extra headaches of their own.

The good news is that the pattern moves, and when researchers pooled 55 studies, biofeedback training gave a medium-sized drop in attacks that held for well over a year, and worked best with practice at home.

In a trial of 232 adults, a short behaviour program added to medicine beat either one alone. Another trial found 40 minutes of exercise three times a week cut attacks about as much as relaxation or a daily preventive drug.

One old belief deserves retiring: that migraine pain comes from swollen blood vessels in the head. When researchers scanned 19 women during real attacks, the vessels outside the skull did not widen, and those inside widened only slightly.

Leading researchers now describe the vessel theory as a good story wrecked by the facts. The pain is about how the brain and its pain nerves handle signals, which is also where stress acts.

Triggers are less certain than they feel, because when 27 people were exposed to the triggers they named, only 6 went on to an attack. Early warning signs, like tiredness and poor focus, can also be mistaken for causes.

Stress care does not always cut attack counts. In a trial of 89 adults, mindfulness training did not reduce migraine days more than a simple education class, though it did ease disability and low mood. It is worth trying, not a promise.