Morning headache could signal something more serious
Many people wake up in the morning with a headache. Simple headache may represent different warning signs of something more serious.
Narrowing of the airway
People with narrow airway may not feel it during daytime. The airway will be narrower when they sleep. It becomes more difficult to breathe and result in mild hypoxia and increased carbon dioxide concentration in the body. People may have headache and dizziness when they wake up.
Too much sleep
When you sleep, your breathing will slow down and carbon dioxide will accumulate. If you sleep for too long, increased carbon dioxide concentration in your body can cause headaches when you wake up.
Obstructive sleep apnea
People with obstructive sleep apnea are similar to people with narrow airway, but the condition is more serious. They often stop breathing during sleep and result in mild hypoxia. People with obstructive sleep apnea often instinctively breathe through their mouths. When they wake up, their mouths feel dry.
Lack of sleep
Not getting enough sleep can also cause morning headache. Lack of sleep can increase the concentration of Catecholamine or Norepinephrine in the body, result in headache.
There is a special type of headache which solely begins during sleep. Hypnic headache is rare and occur most commonly after age 50. It usually occurs within few hours after falling asleep, and it causes people to wake up with pain. When they wake up, they may have headache due to lack of sleep.