A migraine attack is a neurological event that goes far beyond a bad headache. It unfolds in up to four distinct phases over hours or even days, involving changes in brain activity, nerve signaling, and sensitivity to normal stimuli like light, sound, and movement. Most attacks last between 4 and 72 hours, though the full experience, including the buildup and recovery, can stretch considerably longer.
What Happens in Your Brain During an Attack
At the core of a migraine attack is a signaling molecule called CGRP, a small protein found in high concentrations along the pain-sensing nerve pathway that runs from your brainstem to your face and head (the trigeminal system). During an attack, CGRP levels spike in the blood and saliva. This molecule sensitizes nerve cells in the trigeminal system, making them fire more easily. The result is that ordinary stimuli, things like ambient light or the pressure of bending over, start registering as pain. This heightened nerve sensitivity is why migraine pain feels so different from a regular headache.
For the roughly one-third of people who experience aura (visual disturbances, tingling, or speech changes), there’s an additional phenomenon: a slow wave of electrical disruption spreads across the surface of the brain, temporarily flattening normal brainwave activity. Researchers have hypothesized this process since the 1940s, but it was only recently captured directly via electrodes in a patient’s brain. The suppressed activity can last for hours and corresponds to the visual distortions, blind spots, or shimmering patterns people describe during aura.
The Four Phases of a Migraine Attack
Prodrome
Hours or even days before the headache begins, many people notice subtle warning signs. These include mood changes like irritability or depression, difficulty focusing, fatigue, neck stiffness, and sensitivity to light and sound. Some symptoms are surprisingly specific to this phase: excessive yawning, food cravings, and frequent urination. Not everyone recognizes their prodrome at first, but learning to spot it can offer a valuable window for early treatment.
Aura
About one in three people with migraine experience aura, which typically builds over at least five minutes and lasts up to 60 minutes, though it extends beyond an hour in roughly 20% of cases. The most common form is visual: geometric patterns, flashing lights, shimmering spots, or blind areas that appear in both eyes. Some people also get tingling in their hands or face, or temporary difficulty finding words. Aura usually precedes the headache phase but can overlap with it.
Headache
This is the phase most people think of when they hear “migraine.” The pain typically affects one or both sides of the head with a pulsating quality and ranges from moderate to severe. It lasts anywhere from several hours to three days. What sets it apart from other headaches is that it gets worse with routine physical activity. Walking up stairs, turning your head quickly, or even standing up can intensify the pain. Alongside the headache, you may experience nausea or vomiting, anxiety, insomnia, and pronounced sensitivity to light, sound, and smell. Everyday actions like turning on a lamp can feel unbearable.
Postdrome
About 80% of people experience a “migraine hangover” after the pain subsides. This postdrome phase can last anywhere from a few hours to two full days. Common symptoms include deep fatigue, body aches (especially a stiff neck), difficulty concentrating, dizziness, and lingering light sensitivity. Some people describe feeling foggy or washed out. Interestingly, a small number of people feel a brief sense of euphoria during postdrome, though exhaustion is far more typical.
How Migraine Differs From Other Headaches
A tension headache produces mild to moderate pressure that feels like a tight band around your head. It can radiate to the neck and upper back, lasts 30 minutes to several hours, and generally doesn’t include nausea, vomiting, or sensitivity to light. You can usually push through daily activities with a tension headache. A migraine, by contrast, forces most people to stop what they’re doing.
Cluster headaches are a different beast entirely. They cause extreme, piercing pain on one side of the head, usually centered behind the eye, and last about 30 minutes per episode. They arrive in predictable clusters over days or weeks, often striking at the same time each day. Between episodes, the pain disappears completely. Migraine pain is longer-lasting and comes with a broader set of symptoms.
Clinically, a migraine is identified when someone has experienced at least five attacks lasting 4 to 72 hours, with the headache meeting at least two of these characteristics: one-sided location, pulsating quality, moderate-to-severe intensity, or worsening with routine activity. At least one additional symptom must also be present: either nausea/vomiting or sensitivity to both light and sound.
Common Triggers
Migraine attacks rarely come out of nowhere. Most people can identify patterns over time. The most well-documented triggers include hormonal fluctuations (especially drops in estrogen around menstrual periods, during pregnancy, or in perimenopause), stress, sleep changes (both too little and too much), skipped meals, weather shifts, and sensory overload from bright lights or strong smells.
Dietary triggers include alcohol (red wine is a frequent culprit), excessive caffeine, aged cheeses, and highly processed foods. Hormonal medications like oral contraceptives can also worsen migraine frequency or severity for some people. Triggers are highly individual, and most attacks result from a combination of factors rather than a single cause.
Episodic vs. Chronic Migraine
The dividing line between episodic and chronic migraine is 15 headache days per month. If you have 15 or more headache days in a month, with at least 8 of those meeting the criteria for migraine, for three consecutive months, that qualifies as chronic migraine. Anything below that threshold is considered episodic. This distinction matters because treatment strategies differ significantly, and chronic migraine is associated with greater disability and a higher likelihood of benefiting from preventive therapy.
How Treatments Target the Attack
The most widely used class of acute migraine medications works by activating specific receptors on blood vessels and nerve endings in the brain, narrowing dilated vessels and calming the overactive trigeminal nerve signaling that drives the pain. These medications are most effective when taken early in an attack, ideally during prodrome or at the first sign of headache.
A newer class of medications takes a different approach, directly blocking CGRP from binding to its receptors in the trigeminal system. By interrupting the pain cascade at its source, these drugs stop the nerve sensitization that makes normal stimuli painful. They don’t constrict blood vessels, which makes them an option for people with heart disease or other vascular conditions who can’t safely use older migraine medications.
For people with frequent attacks, preventive treatments aim to reduce the number and severity of episodes over time rather than stopping individual attacks. These range from daily oral medications to monthly injections that neutralize CGRP before it can trigger the cascade. The goal is to push someone from chronic territory back below that 15-day-per-month threshold, or to meaningfully reduce attack frequency for those with episodic migraine who still lose multiple days each month.