Migraine triggers: what the evidence really says

Migraine triggers are factors that may set off a migraine attack in someone who already has migraine, such as lack of sleep, hormonal changes or certain medicines. They do not cause migraine: the cause is an inherited sensitivity of the brain. The scientific evidence that avoiding triggers reduces attacks is limited, so searching obsessively for them is rarely worthwhile.

What triggers migraines?

Many people with migraine ask themselves after each attack: why now? It is natural to look for the cause in whatever happened just before, such as food, the weather or a busy day. Over time this produces a long list of possible triggers. Although many sources say that identifying triggers is essential for getting better, there is no convincing scientific evidence that this approach works. Research into migraine triggers is limited and often inconclusive. That is why our migraine specialists advise patients not to search obsessively for specific triggers.

Why can the focus on triggers be misleading?

A migraine clinic mainly sees people who still have frequent attacks despite their efforts to avoid triggers. People for whom avoiding triggers works well rarely need a specialist. This is called selection bias: only the most severe cases reach a specialist, and that can colour a specialist's view of how well trigger avoidance works.

Is migraine your fault?

No. Living without triggers rarely makes migraine disappear completely, and many people have already made numerous changes to their lives without success. The idea that avoiding foods such as alcohol, cheese and chocolate can stop migraine is too simplistic and not well founded. Advice like this can wrongly make people feel that their migraine is their own fault. It is not.

Why is trigger research so difficult?

Much of the research into triggers relies on questionnaires. People tend to report what they believe to be true, which is not necessarily what has been proven. Double-blind, placebo-controlled experiments, in which neither the participant nor the researcher knows whether the real substance was given, are rare and have only been done for a few substances, such as chocolate.

Some apparent triggers are in fact early signs of an attack that has already begun. Craving sweet food, yawning or sensitivity to light can appear hours before the headache, which makes it easy to blame the chocolate rather than the attack that was already on its way.

Can exercise trigger a migraine?

Exercise is often named as a trigger, yet there is also evidence that regular physical activity can help reduce migraine. That contradicts the old idea that rest is always better for your health. Current thinking is that physical activity is generally beneficial, including for people with a long-term condition such as migraine. Some people find it helps to build up gradually.

Does sleep affect migraine?

Sleep problems can act as a trigger. Too little sleep may affect how well the brain functions and clears waste products, which can make an attack more likely. A regular sleep routine helps many people, and in some cases professional help for sleep problems is worthwhile.

Can food trigger a migraine?

The idea that certain foods trigger migraine is widespread, with chocolate, aged cheese and alcohol as the usual suspects. However, scientific evidence that these foods consistently set off attacks is limited. Be careful about cutting foods out of your diet without clear evidence of their effect: a restrictive diet adds a burden without a guaranteed benefit.

Are the weather and medicines migraine triggers?

Changes in the weather are often mentioned as triggers. Whether that is useful advice is doubtful, given the wide range of weather conditions people identify as triggers, and the fact that nobody can avoid the weather. Certain medicines, however, such as vasodilators (medicines that widen blood vessels), have been shown scientifically to trigger migraine attacks.

What can you do about migraine triggers?

• Keep a headache diary for at least three months. Note your headache days, symptoms, medicines and, if you like, possible triggers. A diary often shows that a suspected trigger is less closely linked to your attacks than it seemed.
• Avoid obsessive avoidance. Cutting out more and more foods and activities can make your life smaller without reducing your attacks. If a trigger is clear and easy to avoid, avoiding it is reasonable. If it is not, let it go.
• Keep a steady rhythm where you can. Some people find regular sleep and regular meals help.
• Focus on treatment. Effective acute and preventive treatment usually makes a bigger difference than avoiding triggers.

Finding the right treatment

Triggers are complex. Some seem clear and consistent, but avoiding them is rarely enough on its own to bring migraine under control. If you have frequent attacks, a migraine specialist can look at acute and preventive treatment with you. Read more about what migraine is, explore our treatment, or take the migraine test.