A brain that over-responds to sensory stimuli uses up a lot of energy. And if the brain isn’t getting enough, the nervous system malfunctions.

As well as being amazingly powerful, our brain – the central organ that enables us to think and regulates every process in our body – is one of the biggest energy-consuming organs of them all, using up about 20% of the energy we need in a day. Although brain nerve cells (neurons) are highly energy-efficient, they’re also very sensitive and work best in a stable environment. Part of that is a continuous and plentiful supply of rapidly utilizable energy as fuel. Glucose provides this. Despite needing a lot of energy, our brain does not have a large energy storage system. Our metabolism steps in with ready supplies of glucose to fuel the demand, and an intricate network of blood vessels carries it to where it’s needed.

A consistent supply of energy is crucial for neurons in particular. Even minor fluctuations may interfere with proper functioning, potentially causing a number of neurological disorders – including migraine attacks. That’s why keeping blood sugar levels stable is so important for people with migraine. The best way to accomplish this is by eating several main meals and snacks spread throughout the day and making sure you get enough carbohydrates. A light snack before going to bed helps keep your energy supply stable at night.

Neurons now release pain-triggering chemical messengers (neurotransmitters) non-stop. The blood vessels in the membranes that protect the brain become inflamed, setting off a throbbing headache.

The current understanding is that blood vessels in the brain are the starting point for a migraine event. Nerve endings in the vessels send out signals to warn the brain about impending vascular damage. The brain reacts with a protective response, resulting in the release of chemical messengers that widen the blood vessels. The end result is neurogenic inflammation, which ultimately triggers the pain.

Some nervous system chemical messengers (neuropeptides and other neurotransmitters) also play a key role in these processes. One of them is serotonin, which may be involved in initiating and ending a migraine attack. What we do know for sure is that a fall in serotonin levels in the blood might be part of the cascade of events resulting in a migraine attack. Another indication of serotonin’s important role is that anti-migraine drugs (‘serotonin receptor agonists’) replace the lost serotonin, in that way suppressing the neurogenic inflammation associated with migraine.

Researchers have also identified other chemical messengers as potential targets for novel medicines, including antibody-based drugs that block certain docking sites (receptors) of those substances. This is a vibrant area of research right now.

Basically anything that disrupts the flow of energy to the brain can trigger a migraine, for example:

› skipping meals › not taking enough fluids

› an irregular sleep schedule

› not enough exercise

› not enough relaxation

› poor ergonomics in the workplace

About 10% of people with migraine experience an aura ahead of an attack. Migraine aura happens when the nervous system is fatigued. An aura manifests with neurological symptoms such as

› Visual symptoms: zigzagging lines, flickering and flashes of light, blurred vision and blind spots

› Sensory symptoms (tingling, pins and needles in the fingertips)

› Numbness, paralysis, poor coordination (feeling dizzy, clumsy gait)

› Speech and language symptoms, confusion or mental clouding

Migraineurs may experience a prodrome (pre-headache phase) about 4 to 48 hours before an actual attack. Early warning signs – not to be confused with root causes – may include:

› A creative high, elevated mood, restlessness

› Feeling low, fatigue/no energy, irritability

› Yawning, food cravings (chocolate...), feeling cold, sweating

The actual migraine attack typically begins in the morning and lasts 4 to 72 hours. The pain is pulsing, throbbing, pounding and one-sided. Physical exertion and movement make it worse.

Pain intensity is moderate to very severe. Most people also experience nausea (or actual vomiting) and hypersensitivity to light, noise and/or smells.

You may feel drained and more sensitive to pain (your scalp may be sore to the touch, for example) for up to 2 days after a migraine attack. Some people experience sudden stabbing pain during this stage, and many need much more sleep than usual. Studies show that postdrome lasts about 24 hours on average, but may be as long as 14 days in migraine with aura.