What Causes Headaches? Common Triggers and When to Worry

Headaches are one of the most common health complaints, and most are not a sign of anything serious. In the vast majority of cases the headache itself is the problem, triggered by everyday factors such as dehydration, poor sleep, stress or muscle tension in the neck and jaw. Far less often, a headache is a symptom of another condition that needs medical attention.

This guide explains what causes headaches, the main types, how to work out your own triggers and the warning signs that need urgent help.

When to get help: get urgent help for a sudden, severe headache or one with fever, a stiff neck, confusion or weakness. See your GP if headaches are frequent or getting worse. If they keep returning, a headache diary helps you spot triggers, and NICE recognises acupuncture for preventing tension headaches and migraine. A 60-minute acupuncture session in Chiswick is £80. Book online or call 020 4515 0000.

Quick answer

Most headaches are caused by a combination of everyday triggers: not drinking enough, skipping meals, poor or irregular sleep, stress, long hours at a screen, neck and jaw tension, alcohol, caffeine changes and hormonal shifts. Taking painkillers too often can itself cause daily headaches. A sudden, severe headache, or a headache with weakness, confusion, a stiff neck and fever, needs a 999 call.

Primary and secondary headaches

Doctors divide headaches into two groups. Primary headaches, such as tension-type headache and migraine, are conditions in their own right and account for most headaches. Secondary headaches are caused by something else, such as a cold, a hangover, a head injury or, rarely, a serious problem inside the head.

The main types of headache

• Tension-type headache. The most common type. A dull, tight pressure, like a band around the head, usually on both sides.
• Migraine. A throbbing, often one-sided headache with nausea and sensitivity to light and sound, sometimes with visual disturbance beforehand. See our page on migraine.
• Cervicogenic headache. Pain that starts in the neck and spreads into the head, often worse with certain neck positions.
• Medication overuse headache. A daily or near-daily headache caused by taking painkillers too often.
• Cluster headache. Rare but severe pain around one eye, often with a watery eye and runny nostril on the same side, coming in bouts.

Everyday triggers

• Dehydration and skipped meals
• Too little, too much or irregular sleep
• Stress, and the let-down period after stress, such as weekends and holidays
• Screens and posture. Long periods looking down at a laptop or phone strain the neck and shoulders.
• Jaw clenching and teeth grinding, often at night. See our guide to easing TMJ jaw pain.
• Caffeine. Both too much and suddenly cutting down can trigger headaches.
• Alcohol, especially in larger amounts
• Hormonal changes around periods, pregnancy and the menopause
• Uncorrected eyesight problems, which an eye test can check
• Colds, flu and sinus infections

Can neck tension cause headaches?

Yes. Tight muscles in the neck, shoulders and scalp are closely linked with tension-type headaches, especially after long hours at a desk or looking down at a phone. A cervicogenic headache is different: it starts in the joints or tissues of the upper neck, is usually on one side, begins at the back of the head and spreads forwards, and is often worse with certain neck movements or postures. Both often improve when the neck is treated with exercises, posture changes and hands-on treatment. See how to relieve a tension headache and our physiotherapy in Chiswick.

Can painkillers cause headaches?

Yes. Taking painkillers such as paracetamol, ibuprofen or aspirin on 15 or more days a month, or codeine-based painkillers or triptans on 10 or more days a month, can lead to medication overuse headache. The headache often improves after the painkiller is stopped or reduced, but this should be planned with your GP, as headaches can get worse for a short time before they get better.

Why do I keep getting headaches?

Frequent headaches usually have more than one cause working together, such as poor sleep, stress, neck tension and regular painkiller use. Keeping a headache diary for a few weeks, noting when headaches start, what you were doing, what you ate and drank, your sleep and any medicine taken, is the most reliable way to spot your pattern. How long each headache lasts is another useful clue, covered in how long headaches last.

What helps

Drink water, eat if you have missed a meal, take a screen break and get fresh air. Gentle neck and shoulder stretches and relaxing the jaw help tension headaches. Over the longer term, regular sleep, meals and activity, and treating neck and jaw tension, reduce how often headaches happen. NICE guidance says a course of up to ten acupuncture sessions can be considered to prevent chronic tension-type headache and migraine. For exercises, see neck pain exercises.

When to seek medical help

Call 999 if you have:

• A sudden, severe headache that peaks within about five minutes, often described as the worst headache ever
• A headache with weakness, numbness, drooping of the face, slurred speech, confusion or loss of vision
• A headache with fever, a stiff neck and a rash, or a fit
• A headache after a head injury with vomiting, drowsiness or confusion

Get same-day medical advice, from your GP or NHS 111, if:

• You are over 50 and have a new headache with scalp tenderness or jaw pain when chewing, as this can be a sign of temporal arteritis, which can affect your sight
• You have a headache with a painful red eye and blurred vision
• You are pregnant and have a severe headache with vision problems or sudden swelling of the face, hands or feet
• You have a weakened immune system or a history of cancer and develop a new headache

See your GP if:

• Headaches are frequent, getting worse or have changed in character
• A headache is worse when you cough, strain or lie down, or wakes you from sleep
• You are taking painkillers for headaches on many days each month

Frequently asked questions

Why do I have a headache every day?

Daily headaches are often caused by painkiller overuse, ongoing stress, poor sleep or neck tension. Any new daily headache should be checked by your GP.

Can dehydration cause a headache?

Yes. Even mild dehydration can trigger a headache. Drinking regularly through the day helps prevent this.

Can stress cause headaches?

Yes. Stress is one of the most common triggers for tension-type headaches and migraines, often through muscle tension and poor sleep.

Should I worry about a headache that will not go away?

Most persistent headaches are not serious, but a headache lasting several days, getting worse, or coming with any of the warning signs above should be checked by a doctor.

What causes sudden headaches?

A headache that comes on quickly is most often triggered by dehydration, exertion, coughing or straining, very cold food or drink, or the start of a migraine. A headache that comes on suddenly and is extremely painful, reaching its peak within about five minutes, needs a 999 call, as it can be a sign of bleeding on the brain. A first headache brought on by exercise or sex should also be checked by a GP.

Headache support in Chiswick

Headaches are assessed and treated at Omnia Lifestyle, 8 to 9 Bedford Corner, The Avenue, Chiswick W4 1LZ, close to Turnham Green station, on bus routes 94, E3 and 272. Limited parking is available on request when booking. We take a full headache history and check your neck, jaw and shoulders, and we ask you to keep your GP involved where medication is part of your care. Traditional acupuncture sessions last 60 minutes and cost £80, and a physiotherapy initial assessment and treatment costs £99. See acupuncture for migraines for how a course of treatment works.

Read more about headaches and migraines and neck and shoulder pain, see acupuncture for neck pain, explore acupuncture, physiotherapy and manual therapy, or book an appointment.

This article is general information, not medical advice. If you have any of the warning signs listed above, seek medical attention.