Why does sleep apnea cause headaches

Sleep apnea headaches in the morning are just one common side-effect of the syndrome. Headaches are most commonly experienced by patients with moderate to severe sleep apnea when the oxygen level drops due to the intermittent breathing caused by obstructive sleep apnea OSA.

Sleep apnea causes air to be trapped in the lungs, and this de-oxygenated air is the waste product carbon dioxide. It builds up in the lungs and recycles into the bloodstream. This lack of oxygen in the bloodstream, along with a build-up of carbon dioxide, negatively affects the brain and leads to sleep apnea headaches.

According to Dr. Mark Edward Abramson, sleep apnea and TMJ specialist with the California Center for Craniomandibular Disorders, it is this increased level of carbon dioxide that causes the headache.

This dilation results in a migraine-like headache that is throbbing and irritating. There are some important differences between sleep apnea headaches and migraines, though.

The different types of headaches that can be caused by sleep apnea include: Cluster headaches - Headaches that occur in clusters or patterns during cluter periods that may last for weeks or months. Hypnic headaches - Moderate throbbing headaches that wake the sufferer up one or more times during the night. Each polysomnographic study was scored manually and interpreted by a trained clinical polysomnographer.

Although this classification tends to increase OSA severity in some cases, we believe it is a more accurate measure of the OSA severity because it takes into account the duration of apnea, which would be reflected in part by the degree of oxygen desaturation.

All 80 patients were interviewed about their headache history by one of us N. The patient's sleep disorder was not made known tothe interviewer until after the interview. Patients experiencing 3 or more headaches in the past 1 year were included. The headaches were classified according to International Headache Society criteria.

Headache characteristics were compared with those of a control group of 22 patients with periodic limb movement disorder PLMD , as diagnosed with the criteria recommended by the American Sleep Disorder Association.

Patients with snoring, upper airway resistance syndrome, 13 , 14 and other medical disorders characterized by headaches were excluded from the control group. Headache severity was measured by the Chronic Pain Index. Age ranged from 24 to 86 years, with a mean of Sixteen patients had mild, 23 had moderate, and 41 had severe OSA. Seven patients had 2 types of headaches and 3 patients had 3 types of headaches.

Two of the 23 patients with awakening headaches reported recurrence of headaches after afternoon naps and another 2 patients with positional supine OSA had improvement of headaches after changing sleep positions.

The PLMD control group consisted of 12 women and 10 men, aged 24 to 86 years mean age, The proportion of the various headache types was similar to the OSA group Table 4. None experienced awakening headaches. Arousals in the PLMD group range, 7. Statistical tests for trends were used as the patients with OSA were divided into 3 groups of increasing OSA severity.

Likewise, there was a positive correlation between oxygen desaturation and occurrence of awakening headaches. Oxygen desaturation was also closely related to the severity of awakening headaches Table 6 , right side. No consistent feature regarding nature and location of awakening headaches was observed. Nine patients described their awakening headaches as sharp, 6 as dull, 4 as throbbing, and 4 as nonspecific in nature.

The location was occipital in 8 patients, frontal in 6, transcranial in 5, and shifted from one location to another in 4. Response of awakening headaches to treatment was different compared with other headache types. This included 17 patients with severe, 4 with moderate, and 4 with mild OSA. Marked improvement was seen in patients with morning headaches and cluster headaches.

To determine if patients with OSA wake up with morning headaches involved many issues. The first issue pertains to selection of an appropriate control group. We had to be certain that these morning headaches also were not consistent features in patients with other sleep-related disorders.

Therefore, we chose as our control group patients with PLMD. Patients with evidence of snoring were excluded from the control group because we could not be certain they did not have OSA based on just one polysomnogram. This was important, as earlier studies that disputed the association of OSA and awakening headaches included snorers in their control groups. Had they excluded snorers, they might have found a similar association. Next, we had to be certain that awakening headaches were not due to an exacerbation of a preexisting headache syndrome.

This was done by taking a careful history to ensure that these headaches did not have characteristics resembling those of migraine, tension, cluster, and cervicogenic headaches and other forms of headaches. That 2 patients had recurrence of their headaches on awakening from their afternoon naps and another 2 patients with positional supine OSA showed improvement of their headaches upon changing their sleep positions helped further strengthen the association between OSA and awakening headaches.

You can prepare by taking a brief sleep quiz and talking with your doctor about the results. Your doctor may refer you to a sleep specialist for a sleep study, which can take place in a sleep lab or even in your own home. During the test, sensors will collect your sleep data, which a sleep specialist will use to determine if you have sleep apnea.

If test results indicate that you do have sleep apnea, treating this condition could possibly help reduce your headaches. The sleep specialist can help determine which treatment option is best for you.