Headaches: What causes them?

Did you wake up with a dull throb building behind your eyes this afternoon? Or perhaps a tension band tightening around your skull after staring at screens all day?

We label it a headache.

Most people assume headaches signal something wrong with their brain. But here’s the truth. A headache rarely has anything to do with the brain.

Your brain itself has no pain receptors. It cannot feel pain. What you experience as a headache comes from the tissues surrounding your brain.

Blood vessels, muscles, nerves, and protective membranes. When these tissues become irritated or compressed, they trigger pain signals.

So what irritates them?

Start with blood vessels. When they dilate or constrict abnormally, they activate nearby pain receptors.

This happens during dehydration, when blood volume drops and vessels compensate by widening.

It occurs with caffeine withdrawal as vessels rebound from their normally constricted state. It underlies migraines, where vessels undergo complex inflammatory changes.

Next let us look at muscle tension. The muscles of your scalp, neck, and jaw contain dense networks of pain fibers.

Prolonged contraction from poor posture, eye strain, or jaw clenching reduces blood flow to these muscles.

Reduced blood flow means less oxygen delivery and metabolic waste accumulation. This chemical environment activates pain pathways, creating the characteristic pressure sensation.

Your nervous system adds another layer. The trigeminal nerve, which serves your face and head, becomes hypersensitive under certain conditions.

Insufficient sleep, blood sugar fluctuations, or inflammatory states. Once sensitized, normal stimuli like light, sound, or movement trigger exaggerated pain responses.

Environmental factors converge on these mechanisms. Screen time strains eye muscles and reduces blinking, leading to dehydration.

Skipped meals drop blood glucose, stressing both vascular and nervous systems. Poor sleep prevents the cells in your brain from clearing metabolic waste, priming tissues for inflammation.

So what can you do?

First, figure out your root cause. Headaches cluster when you’re stressed, tired, or dehydrated. These states don’t cause separate problems.

They converge on the same underlying systems. Vascular tone, muscle tension, and nerve sensitivity.

When you understand this, the road to preventing headaches becomes clear.

NB: Headaches are complex phenomena and this article by no means aims to address all the myriad causes.

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